Programs & Examples On #Uidevice

UIDevice uniqueIdentifier deprecated - What to do now?

The MAC address can be spoofed which makes such an approach useless for tying content to specific users or implementing security features like blacklists.

After some further research it appears to me that we're left without a proper alternative as of now. I seriously hope Apple will reconsider their decision.

Maybe it would be a good idea to email Apple about this topic and / or file a bug / feature request on this since maybe they are not even aware of the full consequences for developers.

How much data / information can we save / store in a QR code?

QR codes have three parameters: Datatype, size (number of 'pixels') and error correction level. How much information can be stored there also depends on these parameters. For example the lower the error correction level, the more information that can be stored, but the harder the code is to recognize for readers.

The maximum size and the lowest error correction give the following values:
Numeric only Max. 7,089 characters
Alphanumeric Max. 4,296 characters
Binary/byte Max. 2,953 characters (8-bit bytes)

How to assign multiple classes to an HTML container?

Just remove the comma like this:

<article class="column wrapper"> 

Get all files modified in last 30 days in a directory

A couple of issues

  • You're not limiting it to files, so when it finds a matching directory it will list every file within it.
  • You can't use > in -exec without something like bash -c '... > ...'. Though the > will overwrite the file, so you want to redirect the entire find anyway rather than each -exec.
  • +30 is older than 30 days, -30 would be modified in last 30 days.
  • -exec really isn't needed, you could list everything with various -printf options.

Something like below should work

find . -type f -mtime -30 -exec ls -l {} \; > last30days.txt

Example with -printf

find . -type f -mtime -30 -printf "%M %u %g %TR %TD %p\n" > last30days.txt

This will list files in format "permissions owner group time date filename". -printf is generally preferable to -exec in cases where you don't have to do anything complicated. This is because it will run faster as a result of not having to execute subshells for each -exec. Depending on the version of find, you may also be able to use -ls, which has a similar format to above.

no target device found android studio 2.1.1

try with

sudo adb kill-server
sudo devices


sudo $ANDROID_HOME/platform-tools/adb kill-server 
sudo $ANDROID_HOME/platform-tools/adb devices

c# open file with default application and parameters

Please add Settings under Properties for the Project and make use of them this way you have clean and easy configurable settings that can be configured as default

How To: Create a New Setting at Design Time

Update: after comments below

  1. Right + Click on project
  2. Add New Item
  3. Under Visual C# Items -> General
  4. Select Settings File

Read files from a Folder present in project

If you need to get all the files in the folder named 'Data', just code it as below

string[] Documents = System.IO.Directory.GetFiles("../../Data/");

Now the 'Documents' consists of array of complete object name of two text files in the 'Data' folder 'Data'.

How to copy the first few lines of a giant file, and add a line of text at the end of it using some Linux commands?

I am assuming what you are trying to achieve is to insert a line after the first few lines of of a textfile.

head -n10 file.txt >> newfile.txt
echo "your line >> newfile.txt
tail -n +10 file.txt >> newfile.txt

If you don't want to rest of the lines from the file, just skip the tail part.

Is it possible to get element from HashMap by its position?

Use LinkedHashMap and use this function.

private LinkedHashMap<Integer, String> map = new LinkedHashMap<Integer, String>();

Define like this and.

private Entry getEntry(int id){
        Iterator iterator = map.entrySet().iterator();
        int n = 0;
            Entry entry = (Entry);
            if(n == id){
                return entry;
            n ++;
        return null;

The function can return the selected entry.

Connecting PostgreSQL 9.2.1 with Hibernate

This is the hibernate.cfg.xml file to connect postgresql 9.5 and this is help to you basic configuration.

 <?xml version='1.0' encoding='utf-8'?>

  ~ Hibernate, Relational Persistence for Idiomatic Java
  ~ License: GNU Lesser General Public License (LGPL), version 2.1 or later.
  ~ See the lgpl.txt file in the root directory or <>.
<!DOCTYPE hibernate-configuration SYSTEM
        <!-- Database connection settings -->
        <property name="connection.driver_class">org.postgresql.Driver</property>
        <property name="connection.url">jdbc:postgresql://localhost:5433/hibernatedb</property>
        <property name="connection.username">postgres</property>
        <property name="connection.password">password</property>

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">1</property>

        <!-- SQL dialect -->
        <property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>

        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>

        <!-- Drop and re-create the database schema on startup -->
        <property name="">create</property>
        <mapping class="com.waseem.UserDetails"/>

Make sure File Location should be under src/main/resources/hibernate.cfg.xml

How do you get the cursor position in a textarea?

If there is no selection, you can use the properties .selectionStart or .selectionEnd (with no selection they're equal).

var cursorPosition = $('#myTextarea').prop("selectionStart");

Note that this is not supported in older browsers, most notably IE8-. There you'll have to work with text ranges, but it's a complete frustration.

I believe there is a library somewhere which is dedicated to getting and setting selections/cursor positions in input elements, though. I can't recall its name, but there seem to be dozens on articles about this subject.

What do parentheses surrounding an object/function/class declaration mean?

Juts to follow up on what Andy Hume and others have said:

The '()' surrounding the anonymous function is the 'grouping operator' as defined in section 11.1.6 of the ECMA spec:

Taken verbatim from the docs:

11.1.6 The Grouping Operator

The production PrimaryExpression : ( Expression ) is evaluated as follows:

  1. Return the result of evaluating Expression. This may be of type Reference.

In this context the function is treated as an expression.

How to loop over grouped Pandas dataframe?

Here is an example of iterating over a pd.DataFrame grouped by the column atable. For this sample, "create" statements for an SQL database are generated within the for loop:

import pandas as pd

df1 = pd.DataFrame({
    'atable':     ['Users', 'Users', 'Domains', 'Domains', 'Locks'],
    'column':     ['col_1', 'col_2', 'col_a', 'col_b', 'col'],
    'column_type':['varchar', 'varchar', 'int', 'varchar', 'varchar'],
    'is_null':    ['No', 'No', 'Yes', 'No', 'Yes'],

df1_grouped = df1.groupby('atable')

# iterate over each group
for group_name, df_group in df1_grouped:
    print('\nCREATE TABLE {}('.format(group_name))

    for row_index, row in df_group.iterrows():
        col = row['column']
        column_type = row['column_type']
        is_null = 'NOT NULL' if row['is_null'] == 'NO' else ''
        print('\t{} {} {},'.format(col, column_type, is_null))


Floating Div Over An Image

you might consider using the Relative and Absolute positining.

`.container {  
position: relative;  
.tag {     
position: absolute;   

I have tested it there, also if you want it to change its position use this as its margin:

top: 20px;
left: 10px;

It will place it 20 pixels from top and 10 pixels from left; but leave this one if not necessary.

Get key from a HashMap using the value

  • If you need only that, simply use put(100, "one"). Note that the key is the first argument, and the value is the 2nd.
  • If you need to be able to get by both the key and the value, use BiMap (from guava)

Android: How to use webcam in emulator?


In Android Studio AVD:

  1. Open AVD Manager:

AVD menu

  1. Add/Edit AVD:

Specific AVD strip

  1. Click Advanced Settings in the bottom of the screen:

AVD Advanced Settings

  1. Set your camera of choice as the front/back cameras:

AVD Camera Settings

Get current clipboard content?

Following will give you the selected content as well as updating the clipboard.

Bind the element id with copy event and then get the selected text. You could replace or modify the text. Get the clipboard and set the new text. To get the exact formatting you need to set the type as "text/hmtl". You may also bind it to the document instead of element.

document.querySelector('element').bind('copy', function(event) {
  var selectedText = window.getSelection().toString(); 
  selectedText = selectedText.replace(/\u200B/g, "");

  clipboardData = event.clipboardData || window.clipboardData || event.originalEvent.clipboardData;
  clipboardData.setData('text/html', selectedText);


C# Error "The type initializer for ... threw an exception

This can be caused by not having administrator permissions for Oracle Client. Add this in App.config file:

<IPermission class="Oracle.DataAccess.Client.OraclePermission,
 Oracle.DataAccess, Version=, Culture=neutral,
 PublicKeyToken=89b483f429c47342" version= "1" Unrestricted="true"/>

Error: ANDROID_HOME is not set and "android" command not in your PATH. You must fulfill at least one of these conditions.

If nothing else works, make sure that you have correct permissions and ownership set up during building. A quick fix can be:

sudo chown -R <you>:<your_group> *
sudo chmod -R 755 *

How to make gradient background in android

Visual examples help with this kind of question.


In order to create a gradient, you create an xml file in res/drawable. I am calling mine my_gradient_drawable.xml:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="">
        android:endColor="#115ede" />

You set it to the background of some view. For example:



Set the angle for a linear type. It must be a multiple of 45 degrees.

    android:endColor="#115ede" />

enter image description here


Set the gradientRadius for a radial type. Using %p means it is a percentage of the smallest dimension of the parent.

    android:endColor="#115ede" />

enter image description here


I don't know why anyone would use a sweep, but I am including it for completeness. I couldn't figure out how to change the angle, so I am only including one image.

    android:endColor="#115ede" />

enter image description here


You can also change the center of the sweep or radial types. The values are fractions of the width and height. You can also use %p notation.


enter image description here

What is the most "pythonic" way to iterate over a list in chunks?

In your second method, I would advance to the next group of 4 by doing this:

ints = ints[4:]

However, I haven't done any performance measurement so I don't know which one might be more efficient.

Having said that, I would usually choose the first method. It's not pretty, but that's often a consequence of interfacing with the outside world.

How to read numbers separated by space using scanf

I think by default values read by scanf with space/enter. Well you can provide space between '%d' if you are printing integers. Also same for other cases.

scanf("%d %d %d", &var1, &var2, &var3);

Similarly if you want to read comma separated values use :

scanf("%d,%d,%d", &var1, &var2, &var3);

How the single threaded non blocking IO model works in Node.js

Well, to give some perspective, let me compare node.js with apache.

Apache is a multi-threaded HTTP server, for each and every request that the server receives, it creates a separate thread which handles that request.

Node.js on the other hand is event driven, handling all requests asynchronously from single thread.

When A and B are received on apache, two threads are created which handle requests. Each handling the query separately, each waiting for the query results before serving the page. The page is only served until the query is finished. The query fetch is blocking because the server cannot execute the rest of thread until it receives the result.

In node, c.query is handled asynchronously, which means while c.query fetches the results for A, it jumps to handle c.query for B, and when the results arrive for A arrive it sends back the results to callback which sends the response. Node.js knows to execute callback when fetch finishes.

In my opinion, because it's a single thread model, there is no way to switch from one request to another.

Actually the node server does exactly that for you all the time. To make switches, (the asynchronous behavior) most functions that you would use will have callbacks.


The SQL query is taken from mysql library. It implements callback style as well as event emitter to queue SQL requests. It does not execute them asynchronously, that is done by the internal libuv threads that provide the abstraction of non-blocking I/O. The following steps happen for making a query :

  1. Open a connection to db, connection itself can be made asynchronously.
  2. Once db is connected, query is passed on to the server. Queries can be queued.
  3. The main event loop gets notified of the completion with callback or event.
  4. Main loop executes your callback/eventhandler.

The incoming requests to http server are handled in the similar fashion. The internal thread architecture is something like this:

node.js event loop

The C++ threads are the libuv ones which do the asynchronous I/O (disk or network). The main event loop continues to execute after the dispatching the request to thread pool. It can accept more requests as it does not wait or sleep. SQL queries/HTTP requests/file system reads all happen this way.

How can I access getSupportFragmentManager() in a fragment?

Simply get it like this -

getFragmentManager() // This will also give you the SupportFragmentManager or FragmentManager based on which Fragment class you have extended - OR



in your Fragment's onActivityCreated() method and any method that is being called after onActivityCreated().

jQuery counter to count up to a target number

You can use the jQuery animate function

// Enter num from and to
$({countNum: 99}).animate({countNum: 1000}, {
  duration: 8000,
  step: function() {
    // What todo on every count
  complete: function() {

How to get HttpClient to pass credentials along with the request?

It worked for me after I set up a user with internet access in the Windows service.

In my code:

HttpClientHandler handler = new HttpClientHandler();
handler.Proxy = System.Net.WebRequest.DefaultWebProxy;
handler.Proxy.Credentials = System.Net.CredentialCache.DefaultNetworkCredentials;
HttpClient httpClient = new HttpClient(handler)

What is a non-capturing group in regular expressions?

?: is used when you want to group an expression, but you do not want to save it as a matched/captured portion of the string.

An example would be something to match an IP address:


Note that I don't care about saving the first 3 octets, but the (?:...) grouping allows me to shorten the regex without incurring the overhead of capturing and storing a match.

Get all non-unique values (i.e.: duplicate/more than one occurrence) in an array

var a = ["a","a","b","c","c"];

a.filter(function(value,index,self){ return (self.indexOf(value) !== index )})

Disable ScrollView Programmatically?

Here is a simpler solution. Override the onTouch() for the ScrollView OnTouchListener and return false if you want to bypass the scroll by touch. The programmatic scrolling still works and no need to extend the ScrollView class.

mScroller.setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
  return isScrollable;

Creation timestamp and last update timestamp with Hibernate and MySQL

Following code worked for me.


import java.util.Date;

import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;

import com.fasterxml.jackson.annotation.JsonIgnore;

import org.hibernate.annotations.ColumnDefault;
import org.hibernate.annotations.CreationTimestamp;
import org.hibernate.annotations.UpdateTimestamp;

import lombok.Getter;
import lombok.Setter;

@Getter @Setter
public class BaseEntity {

    @GeneratedValue(strategy = GenerationType.IDENTITY)
    protected Integer id;

    protected Date createdAt;

    protected Date updatedAt;

SQL Query - Using Order By in UNION

SELECT table1Column1 as col1,table1Column2 as col2
    FROM table1
(    SELECT table2Column1 as col1, table1Column2 as col2
         FROM table2

Make index.html default, but allow index.php to be visited if typed in

I agree with @TheAlpha's accepted answer, Apache reads the DirectoryIndex target files from left to right , if the first file exists ,apche serves it and if it doesnt then the next file is served as an index for the directory. So if you have the following Directive :

DirectoryIndex file1.html file2.html

Apache will serve /file.html as index ,You will need to change the order of files if you want to set /file2.html as index

DirectoryIndex file2.html file1.html

You can also set index file using a RewriteRule

RewriteEngine on

RewriteRule ^$ /index.html [L]

RewriteRule above will rewrite your homepage to /index.html the rewriting happens internally so would show you the contents ofindex.html .

CSS: Control space between bullet and <li>

You can just give a padding-left to your <li> element.

How to resolve "local edit, incoming delete upon update" message

I just got this same issue and I found that

$ svn revert foo bar

solved the problem.

svn resolve did not work for me:

$ svn st
!  +  C foo
      >   local edit, incoming delete upon update
!  +  C bar
      >   local edit, incoming delete upon update

$ svn resolve --accept working
svn: Try 'svn help' for more info
svn: Not enough arguments provided

$ svn resolve --accept working .

$ svn st
!  +  C foo
      >   local edit, incoming delete upon update
!  +  C bar
      >   local edit, incoming delete upon update

$ svn resolve --accept working foo
Resolved conflicted state of 'foo'

$ svn st
!  +    foo
!  +  C bar
      >   local edit, incoming delete upon update

What is an IndexOutOfRangeException / ArgumentOutOfRangeException and how do I fix it?

A side from the very long complete accepted answer there is an important point to make about IndexOutOfRangeException compared with many other exception types, and that is:

Often there is complex program state that maybe difficult to have control over at a particular point in code e.g a DB connection goes down so data for an input cannot be retrieved etc... This kind of issue often results in an Exception of some kind that has to bubble up to a higher level because where it occurs has no way of dealing with it at that point.

IndexOutOfRangeException is generally different in that it in most cases it is pretty trivial to check for at the point where the exception is being raised. Generally this kind of exception get thrown by some code that could very easily deal with the issue at the place it is occurring - just by checking the actual length of the array. You don't want to 'fix' this by handling this exception higher up - but instead by ensuring its not thrown in the first instance - which in most cases is easy to do by checking the array length.

Another way of putting this is that other exceptions can arise due to genuine lack of control over input or program state BUT IndexOutOfRangeException more often than not is simply just pilot (programmer) error.

Redirect all output to file using Bash on Linux?

you can use this syntax to redirect all output stderr and stdout to stdout.txt

<cmd> <args> > allout.txt 2>&1 

Create a one to many relationship using SQL Server

If you are not using SSMS then here is the syntax:

ALTER TABLE <table_name>
ADD <constraint_name> FOREIGN KEY 
(<column_name1> ,
<column_name2> )
REFERENCES <table_name>
(<column_name1> ,

Fixed header table with horizontal scrollbar and vertical scrollbar on

This has been driving me crazy for literally weeks. I found a solution that will work for me that includes:

  1. Non-fixed column widths - they shrink and grow on window resizing.
  2. Table has a horizontal scroll-bar when needed, but not when it isn't.
  3. Number of columns is irrelevant - it will size to however many columns you need it to.
  4. Not all columns need to be the same width.
  5. Header goes all the way to the end of the right scrollbar.
  6. No javascript!

...but there are a couple of caveats:

  1. The vertical scrollbar is not visible until you scroll all the way to the right. Given that most people have scroll wheels, this was an acceptable sacrifice.

  2. The width of the scrollbar must be known. On my website I set the scrollbar widths (I'm not overly concerned with older, incompatible browsers), so I can then calculate div and table widths that adjust based on the scrollbar.

Instead of posting my code here, I'll post a link to the jsFiddle.

Fixed header table + scroll left/right.

How do I raise an exception in Rails so it behaves like other Rails exceptions?

You don't have to do anything special, it should just be working.

When I have a fresh rails app with this controller:

class FooController < ApplicationController
  def index
    raise "error"

and go to

I am seeing the exception with a stack trace.

You might not see the whole stacktrace in the console log because Rails (since 2.3) filters lines from the stack trace that come from the framework itself.

See config/initializers/backtrace_silencers.rb in your Rails project

How to verify if a file exists in a batch file?

Here is a good example on how to do a command if a file does or does not exist:

if exist C:\myprogram\sync\data.handler echo Now Exiting && Exit
if not exist C:\myprogram\html\data.sql Exit

We will take those three files and put it in a temporary place. After deleting the folder, it will restore those three files.

xcopy "test" "C:\temp"
xcopy "test2" "C:\temp"
del C:\myprogram\sync\
xcopy "C:\temp" "test"
xcopy "C:\temp" "test2"
del "c:\temp"

Use the XCOPY command:

xcopy "C:\myprogram\html\data.sql"  /c /d /h /e /i /y  "C:\myprogram\sync\"

I will explain what the /c /d /h /e /i /y means:

  /C           Continues copying even if errors occur.
  /D:m-d-y     Copies files changed on or after the specified date.
               If no date is given, copies only those files whose
               source time is newer than the destination time.
  /H           Copies hidden and system files also.
  /E           Copies directories and subdirectories, including empty ones.
               Same as /S /E. May be used to modify /T.
  /T           Creates directory structure, but does not copy files. Does not
               include empty directories or subdirectories. /T /E includes
  /I           If destination does not exist and copying more than one file,
               assumes that destination must be a directory.
  /Y           Suppresses prompting to confirm you want to overwrite an
               existing destination file.

`To see all the commands type`xcopy /? in cmd

Call other batch file with option sync.bat myprogram.ini.

I am not sure what you mean by this, but if you just want to open both of these files you just put the path of the file like


If it was in the Bash environment it was easy for me, but I do not know how to test if a file or folder exists and if it is a file or folder.

You are using a batch file. You mentioned earlier you have to create a .bat file to use this:

I have to create a .BAT file that does this:

FutureWarning: elementwise comparison failed; returning scalar, but in the future will perform elementwise comparison

In my case, the warning occurred because of just the regular type of boolean indexing -- because the series had only np.nan. Demonstration (pandas 1.0.3):

>>> import pandas as pd
>>> import numpy as np
>>> pd.Series([np.nan, 'Hi']) == 'Hi'
0    False
1     True
>>> pd.Series([np.nan, np.nan]) == 'Hi'
~/anaconda3/envs/ms3/lib/python3.7/site-packages/pandas/core/ops/ FutureWarning: elementwise comparison failed; returning scalar instead, but in the future will perform elementwise comparison
  res_values = method(rvalues)
0    False
1    False

I think with pandas 1.0 they really want you to use the new 'string' datatype which allows for pd.NA values:

>>> pd.Series([pd.NA, pd.NA]) == 'Hi'
0    False
1    False
>>> pd.Series([np.nan, np.nan], dtype='string') == 'Hi'
0    <NA>
1    <NA>
>>> (pd.Series([np.nan, np.nan], dtype='string') == 'Hi').fillna(False)
0    False
1    False

Don't love at which point they tinkered with every-day functionality such as boolean indexing.

How to create loading dialogs in Android?

Today things have changed a little.

Now we avoid use ProgressDialog to show spinning progress:

enter image description here

If you want to put in your app a spinning progress you should use an Activity indicators:

How to maintain state after a page refresh in React.js?

So my solution was to also set localStorage when setting my state and then get the value from localStorage again inside of the getInitialState callback like so:

getInitialState: function() {
    var selectedOption = localStorage.getItem( 'SelectedOption' ) || 1;

    return {
        selectedOption: selectedOption

setSelectedOption: function( option ) {
    localStorage.setItem( 'SelectedOption', option );
    this.setState( { selectedOption: option } );

I'm not sure if this can be considered an Anti-Pattern but it works unless there is a better solution.

When to use pthread_exit() and when to use pthread_join() in Linux?

You don't need any calls to pthread_exit(3) in your particular code.

In general, the main thread should not call pthread_exit, but should often call pthread_join(3) to wait for some other thread to finish.

In your PrintHello function, you don't need to call pthread_exit because it is implicit after returning from it.

So your code should rather be:

void *PrintHello(void *threadid)  {
  long tid = (long)threadid;
  printf("Hello World! It's me, thread #%ld!\n", tid);
  return threadid;

int main (int argc, char *argv[]) {
   pthread_t threads[NUM_THREADS];
   int rc;
   intptr_t t;
   // create all the threads
   for(t=0; t<NUM_THREADS; t++){
     printf("In main: creating thread %ld\n", (long) t);
     rc = pthread_create(&threads[t], NULL, PrintHello, (void *)t);
     if (rc) { fprintf(stderr, "failed to create thread #%ld - %s\n",
                                (long)t, strerror(rc));
   pthread_yield(); // useful to give other threads more chance to run
   // join all the threads
   for(t=0; t<NUM_THREADS; t++){
      printf("In main: joining thread #%ld\n", (long) t);
      rc = pthread_join(&threads[t], NULL);
      if (rc) { fprintf(stderr, "failed to join thread #%ld - %s\n",
                                (long)t, strerror(rc));

C# binary literals

C# 7.0 supports binary literals (and optional digit separators via underscore characters).

An example:

int myValue = 0b0010_0110_0000_0011;

You can also find more information on the Roslyn GitHub page.

How to check if a variable is an integer in JavaScript?

Number.isInteger() is the best way if your browser support it, if not, I think there are so many ways to go:

function isInt1(value){
  return (value^0) === value


function isInt2(value){
  return (typeof value === 'number') && (value % 1 === 0); 


function isInt3(value){
  return parseInt(value, 10) === value; 


function isInt4(value){
  return Math.round(value) === value; 

now we can test the results:

var value = 1
isInt1(value)   // return true
isInt2(value)   // return true
isInt3(value)   // return true
isInt4(value)   // return true

var value = 1.1
isInt1(value)   // return false
isInt2(value)   // return false
isInt3(value)   // return false
isInt4(value)   // return false

var value = 1000000000000000000
isInt1(value)   // return false
isInt2(value)   // return true
isInt3(value)   // return false
isInt4(value)   // return true

var value = undefined
isInt1(value)   // return false
isInt2(value)   // return false
isInt3(value)   // return false
isInt4(value)   // return false

var value = '1' //number as string
isInt1(value)   // return false
isInt2(value)   // return false
isInt3(value)   // return false
isInt4(value)   // return false

So, all of these methods are works, but when the number is very big, parseInt and ^ operator would not works well.

What is the difference between @Inject and @Autowired in Spring Framework? Which one to use under what condition?

Better use @Inject all the time. Because it is java configuration approach(provided by sun) which makes our application agnostic to the framework. So if you spring also your classes will work.

If you use @Autowired it will works only with spring because @Autowired is spring provided annotation.

How to change the order of DataFrame columns?

This function avoids you having to list out every variable in your dataset just to order a few of them.

def order(frame,var):
    if type(var) is str:
        var = [var] #let the command take a string or list
    varlist =[w for w in frame.columns if w not in var]
    frame = frame[var+varlist]
    return frame 

It takes two arguments, the first is the dataset, the second are the columns in the data set that you want to bring to the front.

So in my case I have a data set called Frame with variables A1, A2, B1, B2, Total and Date. If I want to bring Total to the front then all I have to do is:

frame = order(frame,['Total'])

If I want to bring Total and Date to the front then I do:

frame = order(frame,['Total','Date'])


Another useful way to use this is, if you have an unfamiliar table and you're looking with variables with a particular term in them, like VAR1, VAR2,... you may execute something like:

frame = order(frame,[v for v in frame.columns if "VAR" in v])

How to set the opacity/alpha of a UIImage?

Hey hey thanks from Xamarin user! :) Here it goes translated to c#

public static class ImageExtensions
    public static UIImage WithAlpha(this UIImage image, float alpha)  
        image.Draw(CGPoint.Empty, CGBlendMode.Normal, alpha);
        var newImage = UIGraphics.GetImageFromCurrentImageContext();
        return newImage;


Usage example:

var MySupaImage = UIImage.FromBundle("opaquestuff.png").WithAlpha(0.15f);

Calling another method java GUI

I'm not sure what you're trying to do, but here's something to consider: c(); won't do anything. c is an instance of the class checkbox and not a method to be called. So consider this:

public class FirstWindow extends JFrame {      public FirstWindow() {         checkbox c = new checkbox();         c.yourMethod(yourParameters); // call the method you made in checkbox     } }  public class checkbox extends JFrame {      public checkbox(yourParameters) {          // this is the constructor method used to initialize instance variables     }      public void yourMethod() // doesn't have to be void     {         // put your code here     } } 

Error: class X is public should be declared in a file named

I had the same problem but solved it when I realized that I didn't compile it with the correct casing. You may have been doing


when it should have been


What is the simplest way to write the contents of a StringBuilder to a text file in .NET 1.1?

I know this is an old post and that it wants an answer for .NET 1.1 but there's already a very good answer for that. I thought it would be good to have an answer for those people who land on this post that may have a more recent version of the .Net framework, such as myself when I went looking for an answer to the same question.

In those cases there is an even simpler way to write the contents of a StringBuilder to a text file. It can be done with one line of code. It may not be the most efficient but that wasn't really the question now was it.


Open link in new tab or window

It shouldn't be your call to decide whether the link should open in a new tab or a new window, since ultimately this choice should be done by the settings of the user's browser. Some people like tabs; some like new windows.

Using _blank will tell the browser to use a new tab/window, depending on the user's browser configuration and how they click on the link (e.g. middle click, Ctrl+click, or normal click).

How to make html <select> element look like "disabled", but pass values?

One could use an additional hidden input element with the same name and value as that of the disabled list. This will ensure that the value is passed in $_POST variables.


<select name="sel" disabled><option>123</select>_x000D_
<input type="hidden" name="sel" value=123>

Fluid or fixed grid system, in responsive design, based on Twitter Bootstrap

Fluid layout in Bootstrap 3.

Unlike Boostrap 2, Bootstrap 3 doesn't have a .container-fluid mixin to make a fluid container. The .container is a fixed width responsive grid layout. In a large screen, there are excessive white spaces in both sides of one's Web page content.

container-fluid is added back in Bootstrap 3.1

A fluid grid layout uses all screen width and works better in large screen. It turns out that it is easy to create a fluid grid layout using Bootstrap 3 mixins. The following line makes a fluid responsive grid layout:


The .container-fixed mixin sets the content to the center of the screen and add paddings. It doesn't specifies a fixed page width.

Another approach is to use Eric Flowers' CSS style

.my-fluid-container {
    padding-left: 15px;
    padding-right: 15px;
    margin-left: auto;
    margin-right: auto;

not:first-child selector

not(:first-child) does not seem to work anymore. At least with the more recent versions of Chrome and Firefox.

Instead, try this:

ul:not(:first-of-type) {}

Change the Right Margin of a View Programmatically?

Update: Android KTX

The Core KTX module provides extensions for common libraries that are part of the Android framework, androidx.core.view among them.

dependencies {
    implementation "androidx.core:core-ktx:{latest-version}"

The following extension functions are handy to deal with margins:

Note: they are all extension functions of MarginLayoutParams, so first you need to get and cast the layoutParams of your view:

val params = (myView.layoutParams as ViewGroup.MarginLayoutParams)

Sets the margins of all axes in the ViewGroup's MarginLayoutParams. (The dimension has to be provided in pixels, see the last section if you want to work with dp)

inline fun MarginLayoutParams.setMargins(@Px size: Int): Unit
// E.g. 16px margins

Updates the margins in the ViewGroup's ViewGroup.MarginLayoutParams.

inline fun MarginLayoutParams.updateMargins(
    @Px left: Int = leftMargin, 
    @Px top: Int = topMargin, 
    @Px right: Int = rightMargin, 
    @Px bottom: Int = bottomMargin
): Unit
// Example: 8px left margin 
params.updateMargins(left = 8)

Updates the relative margins in the ViewGroup's MarginLayoutParams (start/end instead of left/right).

inline fun MarginLayoutParams.updateMarginsRelative(
    @Px start: Int = marginStart, 
    @Px top: Int = topMargin, 
    @Px end: Int = marginEnd, 
    @Px bottom: Int = bottomMargin
): Unit
// E.g: 8px start margin 
params.updateMargins(start = 8)

The following extension properties are handy to get the current margins:

inline val View.marginBottom: Int
inline val View.marginEnd: Int
inline val View.marginLeft: Int
inline val View.marginRight: Int
inline val View.marginStart: Int
inline val View.marginTop: Int
// E.g: get margin bottom
val bottomPx = myView1.marginBottom
  • Using dp instead of px:

If you want to work with dp (density-independent pixels) instead of px, you will need to convert them first. You can easily do that with the following extension property:

val Int.px: Int
    get() = (this * Resources.getSystem().displayMetrics.density).toInt()

Then you can call the previous extension functions like:

params.updateMargins(start = 16.px, end = 16.px, top = 8.px, bottom = 8.px)
val bottomDp = myView1.marginBottom.dp

Old answer:

In Kotlin you can declare an extension function like:

fun View.setMargins(
    leftMarginDp: Int? = null,
    topMarginDp: Int? = null,
    rightMarginDp: Int? = null,
    bottomMarginDp: Int? = null
) {
    if (layoutParams is ViewGroup.MarginLayoutParams) {
        val params = layoutParams as ViewGroup.MarginLayoutParams
        leftMarginDp?.run { params.leftMargin = this.dpToPx(context) }
        topMarginDp?.run { params.topMargin = this.dpToPx(context) }
        rightMarginDp?.run { params.rightMargin = this.dpToPx(context) }
        bottomMarginDp?.run { params.bottomMargin = this.dpToPx(context) }

fun Int.dpToPx(context: Context): Int {
    val metrics = context.resources.displayMetrics
    return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, this.toFloat(), metrics).toInt()

Then you can call it like:

myView1.setMargins(8, 16, 34, 42)


myView2.setMargins(topMarginDp = 8) 

Div 100% height works on Firefox but not in IE

You might have to put one or both of:

html { height:100%; }


body { height:100%; }

EDIT: Whoops, didn't notice they were floated. You just need to float the container.

Accessing Object Memory Address

You could reimplement the default repr this way:

def __repr__(self):
    return '<%s.%s object at %s>' % (

Building a fat jar using maven

You can use the onejar-maven-plugin for packaging. Basically, it assembles your project and its dependencies in as one jar, including not just your project jar file, but also all external dependencies as a "jar of jars", e.g.


Note 1: Configuration options is available at the project home page.

Note 2: For one reason or the other, the onejar-maven-plugin project is not published at Maven Central. However tracks the original project and publishes it to with the groupId com.jolira.

Printing all global variables/local variables?

Type info variables to list "All global and static variable names".

Type info locals to list "Local variables of current stack frame" (names and values), including static variables in that function.

Type info args to list "Arguments of the current stack frame" (names and values).

How to set editor theme in IntelliJ Idea

IntelliJ IDEA seems to have reorganized the configurations panel. Now one should go to Editor -> Color Scheme and click on the gears icon to import the theme they want from external .jar files.

How do I change the font-size of an <option> element within <select>?

Like most form controls in HTML, the results of applying CSS to <select> and <option> elements vary a lot between browsers. Chrome, as you've found, won't let you apply and font styles to an <option> element directly --- if you do Inspect Element on it, you'll see the font-size: 14px declaration is crossed through as if it's been overridden by the cascade, but it's actually because Chrome is ignoring it.

However, Chrome will let you apply font styles to the <optgroup> element, so to achieve the result you want you can wrap all the <option>s in an <optgroup> and then apply your font styles to a .styled-select optgroup selector. If you want the optgroup sans-label, you may have to do some clever CSS with positioning or something to hide the white area at the top where the label would be shown, but that should be possible.

Forked to a new JSFiddle to show you what I mean:

How to create an XML document using XmlDocument?

What about:

#region Using Statements
using System;
using System.Xml;

class Program {
    static void Main( string[ ] args ) {
        XmlDocument doc = new XmlDocument( );

        //(1) the xml declaration is recommended, but not mandatory
        XmlDeclaration xmlDeclaration = doc.CreateXmlDeclaration( "1.0", "UTF-8", null );
        XmlElement root = doc.DocumentElement;
        doc.InsertBefore( xmlDeclaration, root );

        //(2) string.Empty makes cleaner code
        XmlElement element1 = doc.CreateElement( string.Empty, "body", string.Empty );
        doc.AppendChild( element1 );

        XmlElement element2 = doc.CreateElement( string.Empty, "level1", string.Empty );
        element1.AppendChild( element2 );

        XmlElement element3 = doc.CreateElement( string.Empty, "level2", string.Empty );
        XmlText text1 = doc.CreateTextNode( "text" );
        element3.AppendChild( text1 );
        element2.AppendChild( element3 );

        XmlElement element4 = doc.CreateElement( string.Empty, "level2", string.Empty );
        XmlText text2 = doc.CreateTextNode( "other text" );
        element4.AppendChild( text2 );
        element2.AppendChild( element4 );

        doc.Save( "D:\\document.xml" );

(1) Does a valid XML file require an xml declaration?
(2) What is the difference between String.Empty and “” (empty string)?

The result is:

<?xml version="1.0" encoding="UTF-8"?>
    <level2>other text</level2>

But I recommend you to use LINQ to XML which is simpler and more readable like here:

#region Using Statements
using System;
using System.Xml.Linq;

class Program {
    static void Main( string[ ] args ) {
        XDocument doc = new XDocument( new XElement( "body", 
                                           new XElement( "level1", 
                                               new XElement( "level2", "text" ), 
                                               new XElement( "level2", "other text" ) ) ) );
        doc.Save( "D:\\document.xml" );

Is it good practice to use the xor operator for boolean checks?

if((boolean1 && !boolean2) || (boolean2 && !boolean1)) 
  //do it 

IMHO this code could be simplified:

if(boolean1 != boolean2) 
  //do it 

ActionLink htmlAttributes

The problem is that your anonymous object property data-icon has an invalid name. C# properties cannot have dashes in their names. There are two ways you can get around that:

Use an underscore instead of dash (MVC will automatically replace the underscore with a dash in the emitted HTML):

@Html.ActionLink("Edit", "edit", "markets",
      new { id = 1 },
      new {@class="ui-btn-right", data_icon="gear"})

Use the overload that takes in a dictionary:

@Html.ActionLink("Edit", "edit", "markets",
      new { id = 1 },
      new Dictionary<string, object> { { "class", "ui-btn-right" }, { "data-icon", "gear" } });

Yes or No confirm box using jQuery

The alert method blocks execution until the user closes it:

use the confirm function:

if (confirm('Some message')) {
    alert('Thanks for confirming');
} else {
    alert('Why did you press cancel? You should have confirmed');

Pip freeze vs. pip list

For those looking for a solution. If you accidentally made pip requirements with pip list instead of pip freeze, and want to convert into pip freeze format. I wrote this R script to do so.


pip_list = read_lines("requirements.txt")

pip_freeze = pip_list %>%
  str_replace_all(" \\(", "==") %>%
  str_replace_all("\\)$", "")

pip_freeze %>% write_lines("requirements.txt")

How do I configure Notepad++ to use spaces instead of tabs?

I have NotePad++ v6.8.3, and it was in Settings ? Preferences ? Tab Settings ? [Default] ? Replace by space:

NotePad++ Preferences

NotePad++ Tab Settings

From Now() to Current_timestamp in Postgresql

Use an interval instead of an integer:

FROM table
WHERE auth_user.lastactivity > CURRENT_TIMESTAMP - INTERVAL '100 days'

How to simulate browsing from various locations?

Besides using multiple proxies or proxy-networks, you might want to try the planet-lab. (And probably there are other similar institutions around).

The social solution would be to post a question on some board that you are searching for volunteers that proxy your requests. (They only have to allow for one destination in their proxy config thus the danger of becoming spam-whores is relatively low.) You should prepare credentials that ensure your partners of the authenticity of the claim that the destination is indeed your computer.

Youtube - How to force 480p video quality in embed link / <iframe>

I found that as of May, 2012, if you set the frame size so that the minimum pixel area (width • height) is above a certain threshold, it bumps the quality up from 360p to 480p, if you're video is at least 640 x 360.

I've discovered that setting a frame size to 780 x 480 for the embed frame triggers the 480p quality, without distorting the video (scaling up). 640 x 585 also works in this manner. I also used the &hd=1 parameter, but I doubt this has much control if your video is not uploaded in HD (720p or higher).

For instance:

<iframe width="780" height="480" src="[VIDEO-ID]?rel=0&fs=1&showinfo=0&autohide=1&hd=1"></iframe>

Of course, the drawback is that by setting these static frame dimensions, you will most likely get black bars on the sides or above and below, depending on what you prefer.

If you didn't care about the controls being cut-off, you could go on to use CSS and overflow: hidden to crop the black bars out of the frame, providing you know the exact dimensions of the video.

Hope this helps, and hope the Embed method soon gets discrete quality parameters again one day!

Test if string begins with a string?

There are several ways to do this:


You can use the InStr build-in function to test if a String contains a substring. InStr will either return the index of the first match, or 0. So you can test if a String begins with a substring by doing the following:

If InStr(1, "Hello World", "Hello W") = 1 Then
    MsgBox "Yep, this string begins with Hello W!"
End If

If InStr returns 1, then the String ("Hello World"), begins with the substring ("Hello W").


You can also use the like comparison operator along with some basic pattern matching:

If "Hello World" Like "Hello W*" Then
    MsgBox "Yep, this string begins with Hello W!"
End If

In this, we use an asterisk (*) to test if the String begins with our substring.

JavaScript ES6 promise for loop

If you are limited to ES6, the best option is Promise all. Promise.all(array) also returns an array of promises after successfully executing all the promises in array argument. Suppose, if you want to update many student records in the database, the following code demonstrates the concept of Promise.all in such case-

let promises =, index) => {
//where students is a db object
student.rollNo = index + 1; = 'City Name';
//Update whatever information on student you want
Promise.all(promises).then(() => {
  //All the save queries will be executed when .then is executed
  //You can do further operations here after as all update operations are completed now

Map is just an example method for loop. You can also use for or forin or forEach loop. So the concept is pretty simple, start the loop in which you want to do bulk async operations. Push every such async operation statement in an array declared outside the scope of that loop. After the loop completes, execute the Promise all statement with the prepared array of such queries/promises as argument.

The basic concept is that the javascript loop is synchronous whereas database call is async and we use push method in loop that is also sync. So, the problem of asynchronous behavior doesn't occur inside the loop.

Recover SVN password from local cache

On Windows, Subversion stores the auth data in %APPDATA%\Subversion\auth. The passwords however are stored encrypted, not in plaintext.

You can decrypt those, but only if you log in to Windows as the same user for which the auth data was saved.

Someone even wrote a tool to decrypt those. Never tried the tool myself so I don't know how well it works, but you might want to try it anyway:

Update: In TortoiseSVN 1.9 and later, you can do it without any additional tools:

Settings Dialog -> Saved Data, then click the "Clear..." button right of the text "Authentication Data". A new dialog pops up, showing all stored authentication data where you can chose which one(s) to clear. Instead of clearing, hold down the Shift and Ctrl button, and then double click on the list. A new column is shown in the dialog which shows the password in clear.

How to stop a vb script running in windows

Start Task Manager, click on the Processes tab, right-click on wscript.exe and select End Process, and confirm in the dialog that follows. This will terminate the wscript.exe that is executing your script.

How do I restrict my EditText input to numerical (possibly decimal and signed) input?

There's no reason to use setRawInputType(), just use setInputType(). However, you have to combine the class and flags with the OR operator:


AltGr key not working, instead I have to use Ctrl+AltGr

I found a solution for my problem while writing my question !

Going into my remote session i tried two key combinations, and it solved the problem on my Desktop : Alt+Enter and Ctrl+Enter (i don't know which one solved the problem though)

I tried to reproduce the problem, but i couldn't... but i'm almost sure it's one of the key combinations described in the question above (since i experienced this problem several times)

So it seems the problem comes from the use of RDP (windows7 and 8)

Update 2017: Problem occurs on Windows 10 aswell.

Running JAR file on Windows

There are many methods for running .jar file on windows. One of them is using the command prompt.

Steps :

  1. Open command prompt(Run as administrator)
  2. Now write "cd\" command for root directory
  3. Type "java jar filename.jar" Note: you can also use any third party apps like WinRAR, jarfix, etc.

Angularjs error Unknown provider

Make sure you are loading those modules ( and myApp.directives) as dependencies of your main app module, like this:

angular.module('myApp', ['myApp.directives', '']);


How to change identity column values programmatically?

Very nice question, first we need to on the IDENTITY_INSERT for the specific table, after that run the insert query (Must specify the column name).

Note: After edit the the identity column, don't forget to off the IDENTITY_INSERT. If you not done, you cannot able to Edit the identity column for any other table.

     INSERT Emp_tb_gb_Menu(MenuID) VALUES (68)

Letter Count on a string

Your return is in your for loop! Be careful with indentation, you want the line return count to be outside the loop. Because the for loop goes through all characters in word, the outer while loop is completely unneeded.

A cleaned-up version:

def count_letters(word, to_find):
    count = 0
    for char in word:
        if char == to_find:
            count += 1
    return count

Can you target <br /> with css?

My own tests conclusively show that br tags do not like to be targeted for css.

But if you can add style then you can probably also add a scrip tag to the header of the page? Link to an external .js that does something like this:

function replaceLineBreaksWithHorizontalRulesInElement( element )
    elems = element.getElementsByTagName( 'br' );
    for ( var i = 0; i < elems.length; i ++ )
        br = elems.item( i );
        hr = document.createElement( 'hr' );
        br.parentNode.replaceChild( hr, br );

So in short, it's not optimal, but here is my solution.

How to remove constraints from my MySQL table?

this will works on MySQL to drop constraints

alter table tablename drop primary key;

alter table tablename drop foreign key;

Pass variable to function in jquery AJAX success callback

You can also use indexValue attribute for passing multiple parameters via object:

var someData = "hello";

    url: "",
    indexValue: {param1:someData, param2:"Other data 2", param3: "Other data 3"},
    dataType: "script"
}).done(function() {

Update Fragment from ViewPager

If you use Kotlin, you can do the following:

1. On first, you should be create Interface and implemented him in your Fragment

interface RefreshData {
    fun refresh()

class YourFragment : Fragment(), RefreshData {
    override fun refresh() {
        //do what you want

2. Next step is add OnPageChangeListener to your ViewPager

viewPager.addOnPageChangeListener(object : ViewPager.OnPageChangeListener {
    override fun onPageScrollStateChanged(state: Int) { }

    override fun onPageSelected(position: Int) {
        viewPager.currentItem = position

    override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) { }

3. override getItemPosition in your Adapter

override fun getItemPosition(obj: Any): Int {
    if (obj is RefreshData) {
    return super.getItemPosition(obj)

Using the AND and NOT Operator in Python

Use the keyword and, not & because & is a bit operator.

Be careful with this... just so you know, in Java and C++, the & operator is ALSO a bit operator. The correct way to do a boolean comparison in those languages is &&. Similarly | is a bit operator, and || is a boolean operator. In Python and and or are used for boolean comparisons.

In JavaScript can I make a "click" event fire programmatically for a file input element?

This will now be possible in Firefox 4, with the caveat that it counts as a pop-up window and will therefore be blocked whenever a pop-up window would have been.

How to send HTML-formatted email?

Setting isBodyHtml to true allows you to use HTML tags in the message body:

msg = new MailMessage("[email protected]",
                "[email protected]", "Message from PSSP System",
                "This email sent by the PSSP system<br />" +
                "<b>this is bold text!</b>");

msg.IsBodyHtml = true;

Regular expression to return text between parenthesis

Building on tkerwin's answer, if you happen to have nested parentheses like in

st = "sum((a+b)/(c+d))"

his answer will not work if you need to take everything between the first opening parenthesis and the last closing parenthesis to get (a+b)/(c+d), because find searches from the left of the string, and would stop at the first closing parenthesis.

To fix that, you need to use rfind for the second part of the operation, so it would become


Artisan migrate could not find driver

In your php.ini configuration file simply uncomment the extension:


(You can find your php.ini file in the php folder where your server is installed.)

make this to


now you need to configure your .env file in find DB_DATABASE= write in that database name which you used than migrate like if i used my database and database name is "abc" than i need to write there DB_DATABASE=abc and save that .env file and run command again

php artisan migrate

so after run than you got some msg like as:

php artisan migrate
Migration table created successfully.

Library not loaded: libmysqlclient.16.dylib error when trying to run 'rails server' on OS X 10.6 with mysql2 gem

I solved this problem by deleting my gemset for my current project and recreating it and rerunning bundle install. I think I caused it by installing a newer version of mysql.

WCF on IIS8; *.svc handler mapping doesn't work

turn ON the following on 'Turn Windows Features on or off'

a) .Net Framework 3.5 - WCF HTTP Activation and Non-Http Activation

b) all under WCF Services

Install .ipa to iPad with or without iTunes

You can create the ipa for ad hoc distribution and use diawi to create a link for the your ipad. You just upload the .ipa and the provisioning profile, then a link is generated and you can visit it from your ipad in order to install the app (if the provisioning profile is for development you have to add your ipad's UDID to it).

Using variables inside a bash heredoc

Don't use quotes with <<EOF:

sudo tee "/path/to/outfile" > /dev/null <<EOF
Some text that contains my $var

Variable expansion is the default behavior inside of here-docs. You disable that behavior by quoting the label (with single or double quotes).

How can I match multiple occurrences with a regex in JavaScript similar to PHP's preg_match_all()?

Just to stick with the proposed question as indicated by the title, you can actually iterate over each match in a string using String.prototype.replace(). For example the following does just that to get an array of all words based on a regular expression:

function getWords(str) {
  var arr = [];
  str.replace(/\w+/g, function(m) {
  return arr;

var words = getWords("Where in the world is Carmen Sandiego?");
// > ["Where", "in", "the", "world", "is", "Carmen", "Sandiego"]

If I wanted to get capture groups or even the index of each match I could do that too. The following shows how each match is returned with the entire match, the 1st capture group and the index:

function getWords(str) {
  var arr = [];
  str.replace(/\w+(?=(.*))/g, function(m, remaining, index) {
    arr.push({ match: m, remainder: remaining, index: index });
  return arr;

var words = getWords("Where in the world is Carmen Sandiego?");

After running the above, words will be as follows:

    "match": "Where",
    "remainder": " in the world is Carmen Sandiego?",
    "index": 0
    "match": "in",
    "remainder": " the world is Carmen Sandiego?",
    "index": 6
    "match": "the",
    "remainder": " world is Carmen Sandiego?",
    "index": 9
    "match": "world",
    "remainder": " is Carmen Sandiego?",
    "index": 13
    "match": "is",
    "remainder": " Carmen Sandiego?",
    "index": 19
    "match": "Carmen",
    "remainder": " Sandiego?",
    "index": 22
    "match": "Sandiego",
    "remainder": "?",
    "index": 29

In order to match multiple occurrences similar to what is available in PHP with preg_match_all you can use this type of thinking to make your own or use something like YourJS.matchAll(). YourJS more or less defines this function as follows:

function matchAll(str, rgx) {
  var arr, extras, matches = [];
  str.replace( ? rgx : new RegExp(rgx.source, (rgx + '').replace(/[\s\S]+\//g , 'g')), function() {
    matches.push(arr = [];
    extras = arr.splice(-2);
    arr.index = extras[0];
    arr.input = extras[1];
  return matches[0] ? matches : null;

writing a batch file that opens a chrome URL

It's very simple. Just try:

start chrome

it will open the Google page in the Chrome browser.

If you wish to open the page in Firefox, try:

start firefox

Have Fun!

Select default option value from typescript angular 6


<select class='form-control'>
    <option *ngFor="let option of options"
    [selected]="option === nrSelect"
        {{ option }}


nrSelect = 47;
options = [41, 42, 47, 48];

How to check if input file is empty in jQuery

I know I'm late to the party but I thought I'd add what I ended up using for this - which is to simply check if the file upload input does not contain a truthy value with the not operator & JQuery like so:

if (!$('#videoUploadFile').val()) {
  alert('Please Upload File');

Note that if this is in a form, you may also want to wrap it with the following handler to prevent the form from submitting:

$(document).on("click", ":submit", function (e) {

  if (!$('#videoUploadFile').val()) {
  alert('Please Upload File');


How to correctly display .csv files within Excel 2013?

I know that an answer has already been accepted, but one item to check is the encoding of the CSV file. I have a Powershell script that generates CSV files. By default, it was encoding them as UCS-2 Little Endian (per Notepad++). It would open the file in a single column in Excel and I'd have to do the Text to Columns conversion to split the columns. Changing the script to encode the same output as "ASCII" (UTF-8 w/o BOM per Notepad++) allowed me to open the CSV directly with the columns split out. You can change the encoding of the CSV in Notepad++ too.

  • Menu Encoding > Convert to UTF-8 without BOM
  • Save the CSV file
  • Open in Excel, columns should be split

List append() in for loop

The list.append function does not return any value(but None), it just adds the value to the list you are using to call that method.

In the first loop round you will assign None (because the no-return of append) to a, then in the second round it will try to call a.append, as a is None it will raise the Exception you are seeing

You just need to change it to:

for i in range(5):    
# [0, 1, 2, 3, 4]

list.append is what is called a mutating or destructive method, i.e. it will destroy or mutate the previous object into a new one(or a new state).

If you would like to create a new list based in one list without destroying or mutating it you can do something like this:

a=['a', 'b', 'c']
result = a + ['d']

print result
# ['a', 'b', 'c', 'd']

print a
# ['a', 'b', 'c']

As a corollary only, you can mimic the append method by doing the following:

a=['a', 'b', 'c']
a = a + ['d']

print a
# ['a', 'b', 'c', 'd']

jQuery SVG vs. Raphael

You should also take a look at svgweb. It uses flash to render svg in IE, and optionally on other browsers (in the cases where it supports more than the browser itself does).

How to properly validate input values with React.JS?

I recently spent a week studying lot of solutions to validate my forms in an app. I started with all the most stared one but I couldn't find one who was working as I was expected. After few days, I became quite frustrated until i found a very new and amazing plugin:

The developper is very responsive and his solution, after my research, merit to become the most stared one from my perspective. I hope it could help and you'll appreciate.


Join on one-to-many relation in JPQL looks as follows:

select b.fname, b.lname from Users b JOIN b.groups c where c.groupName = :groupName 

When several properties are specified in select clause, result is returned as Object[]:

Object[] temp = (Object[]) em.createNamedQuery("...")
    .setParameter("groupName", groupName)
String fname = (String) temp[0];
String lname = (String) temp[1];

By the way, why your entities are named in plural form, it's confusing. If you want to have table names in plural, you may use @Table to specify the table name for the entity explicitly, so it doesn't interfere with reserved words:

@Entity @Table(name = "Users")     
public class User implements Serializable { ... } 

What does the ">" (greater-than sign) CSS selector mean?

> (greater-than sign) is a CSS Combinator.

A combinator is something that explains the relationship between the selectors.

A CSS selector can contain more than one simple selector. Between the simple selectors, we can include a combinator.

There are four different combinators in CSS3:

  1. descendant selector (space)
  2. child selector (>)
  3. adjacent sibling selector (+)
  4. general sibling selector (~)

Note: < is not valid in CSS selectors.

enter image description here

For example:

<!DOCTYPE html>
div > p {
    background-color: yellow;

  <p>Paragraph 1 in the div.</p>
  <p>Paragraph 2 in the div.</p>
  <span><p>Paragraph 3 in the div.</p></span> <!-- not Child but Descendant -->

<p>Paragraph 4. Not in a div.</p>
<p>Paragraph 5. Not in a div.</p>



enter image description here

More information about CSS Combinators

How to use jQuery to call an ASP.NET web service?

 type: 'POST',
 url: 'data.asmx/getText',
 data: {'argInput' : 'input arg(s)'},
 complete: function(xData, status) {
 $('#txt').html($(xData.responseXML).text()); // result

Html.ActionLink as a button or an image, not a link

A late answer but this is how I make my ActionLink into a button. We're using Bootstrap in our project as it makes it convenient. Never mind the @T since its only an translator we're using.

@Html.Actionlink("Some_button_text", "ActionMethod", "Controller", "Optional parameter", "html_code_you_want_to_apply_to_the_actionlink");

The above gives a link like this and it looks as the picture below:


picture demonstrating button with bootstrap

In my view:

@using (Html.BeginForm())
<div class="section-header">
    <div class="title">
    <div class="addAffiliation">
        <p />
        @Html.ActionLink("" + @T("Admin.Users.AddAffiliation"), "AddAffiliation", "Firms", new { id = (string)@WorkContext.CurrentFirm.ExternalId }, new { @class="btn btn-primary" })


Hope this helps somebody

How to extract the first two characters of a string in shell scripting?

If you're in bash, you can say:

bash-3.2$ var=abcd
bash-3.2$ echo ${var:0:2}

This may be just what you need…

Select Pandas rows based on list index

ind_list = [1, 3]

should do the trick! When I index with data frames I always use the .ix() method. Its so much easier and more flexible...

UPDATE This is no longer the accepted method for indexing. The ix method is deprecated. Use .iloc for integer based indexing and .loc for label based indexing.

What are the different NameID format used for?

About this I think you can reference to

Here're my understandings about this, with the Identity Federation Use Case to give a details for those concepts:

  • Persistent identifiers-

IdP provides the Persistent identifiers, they are used for linking to the local accounts in SPs, but they identify as the user profile for the specific service each alone. For example, the persistent identifiers are kind of like : johnForAir, jonhForCar, johnForHotel, they all just for one specified service, since it need to link to its local identity in the service.

  • Transient identifiers-

Transient identifiers are what IdP tell the SP that the users in the session have been granted to access the resource on SP, but the identities of users do not offer to SP actually. For example, The assertion just like “Anonymity(Idp doesn’t tell SP who he is) has the permission to access /resource on SP”. SP got it and let browser to access it, but still don’t know Anonymity' real name.

  • unspecified identifiers-

The explanation for it in the spec is "The interpretation of the content of the element is left to individual implementations". Which means IdP defines the real format for it, and it assumes that SP knows how to parse the format data respond from IdP. For example, IdP gives a format data "UserName=XXXXX Country=US", SP get the assertion, and can parse it and extract the UserName is "XXXXX".

How do you build a Singleton in Dart?

Here is a comparison of several different ways to create a singleton in Dart.

1. Factory constructor

class SingletonOne {


  static final SingletonOne _instance = SingletonOne._privateConstructor();

  factory SingletonOne() {
    return _instance;


2. Static field with getter

class SingletonTwo {


  static final SingletonTwo _instance = SingletonTwo._privateConstructor();

  static SingletonTwo get instance => _instance;

3. Static field

class SingletonThree {


  static final SingletonThree instance = SingletonThree._privateConstructor();

How to instantiate

The above singletons are instantiated like this:

SingletonOne one = SingletonOne();
SingletonTwo two = SingletonTwo.instance;
SingletonThree three = SingletonThree.instance;


I originally asked this as a question, but discovered that all of the methods above are valid and the choice largely depends on personal preference.

Nginx 403 error: directory index of [folder] is forbidden

In my case I didn't run this command

sudo apt-get install php7.4-fpm

CodeIgniter: 404 Page Not Found on Live Server

Try to add following line in root folder index.php after php starts:


This works for me.

How do I export (and then import) a Subversion repository?

Basically, there are plenty of ways to accomplish the task. The topic is covered in depth in SVNBook | Migrating Repository Data Elsewhere, so I suggest reading the book's section.

Here is a brief description of your options:

  • It depends on your environment, but there is a great chance that you can simply copy the repository to the new server and it will work. You have to revise repository hook scripts after copying the repo to ensure that they are working as you expect.

  • You can use svnadmin dump and svnadmin load commands to, ehm, generate full dump and then load it to another repository on another server. You will need to svnadmin create a new clean repository to load the dump into it. Keep in mind that the approach deals with repository history only and does not move hook scripts and repository configuration files! As well, you must have read filesystem access to the original repository to dump it.

  • Since Subversion 1.7, svnrdump tool is available. Generally speaking, it mimics svnadmin dump and svnadmin load functionality, but operates remotely. You are not required to have read / write filesystem access to original and target repositories as tool operates remotely like Subversion client, e.g. over HTTPS protocol. So you need to have read access to original repository and read / write to the target one.

  • Another option is to use svnadmin hotcopy command. The command is mostly used for backup purpose, it creates full copy of the repository including configuration and hook scripts. You can move hotcopied repository to another server then.

Throwing exceptions in a PHP Try Catch block

Throw needs an object instantiated by \Exception. Just the $e catched can play the trick.

throw $e

Change bootstrap navbar collapse breakpoint without using LESS

Here my working code using in React with Bootstrap

<link rel="stylesheet" href="" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u"
  @media (min-width: 768px) and (max-width: 1000px) {
   .navbar-collapse.collapse {
       display: none !important;
        display: block !important;
        float: none;

How to set default value for form field in Symfony2?

If that field is bound to an entity (is a property of that entity) you can just set a default value for it.

An example:

public function getMyField() {
    if (is_null($this->MyField)) {
        $this->setMyField('my default value');
    return $this->MyField;

design a stack such that getMinimum( ) should be O(1)

Here is my Code which runs with O(1). Here I used vector pair which contain the value which pushed and also contain the minimum value up to this pushed value.

Here is my version of C++ implementation.

vector<pair<int,int> >A;
int sz=0; // to keep track of the size of vector

class MinStack

    void push(int x)
        int mn=(sz==0)?x: min(A[sz-1].second,x); //find the minimum value upto this pushed value
        sz++; // increment the size

    void pop()
        if(sz==0) return;
        A.pop_back(); // pop the last inserted element
        sz--;  // decrement size

    int top()
        if(sz==0)   return -1;  // if stack empty return -1
        return A[sz-1].first;  // return the top element

    int getMin()
        if(sz==0) return -1;
        return A[sz-1].second; // return the minimum value at sz-1 

Truncate with condition

No, TRUNCATE is all or nothing. You can do a DELETE FROM <table> WHERE <conditions> but this loses the speed advantages of TRUNCATE.

How to save all console output to file in R?

If you have access to a command line, you might prefer running your script from the command line with R CMD BATCH.

== begin contents of script.R ==

a <- "a"
How come I do not see this in log

== end contents of script.R ==

At the command prompt ("$" in many un*x variants, "C:>" in windows), run

$ R CMD BATCH script.R &

The trailing "&" is optional and runs the command in the background. The default name of the log file has "out" appended to the extension, i.e., script.Rout

== begin contents of script.Rout ==

R version 3.1.0 (2014-04-10) -- "Spring Dance"
Copyright (C) 2014 The R Foundation for Statistical Computing
Platform: i686-pc-linux-gnu (32-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

  Natural language support but running in an English locale

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

[Previously saved workspace restored]

> a <- "a"
> a
[1] "a"
> How come I do not see this in log
Error: unexpected symbol in "How come"
Execution halted

== end contents of script.Rout ==

How can I set a proxy server for gem?

You can try export http_proxy=http://your_proxy:your_port

How to use a jQuery plugin inside Vue

You need to use either the globals loader or expose loader to ensure that webpack includes the jQuery lib in your source code output and so that it doesn't throw errors when your use $ in your components.

// example with expose loader:
npm i --save-dev expose-loader

// somewhere, import (require) this jquery, but pipe it through the expose loader

If you prefer, you can import (require) it directly within your webpack config as a point of entry, so I understand, but I don't have an example of this to hand

Alternatively, you can use the globals loader like this:

Error: No default engine was specified and no extension was provided

Comment out the res.render lines in your code and add in next(err); instead. If you're not using a view engine, the res.render stuff will throw an error.

Sorry, you'll have to comment out this line as well:

app.set('view engine', 'html');

My solution would result in not using a view engine though. You don't need a view engine, but if that's the goal, try this:

app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
//swap jade for ejs etc

You'll need the res.render lines when using a view engine as well. Something like this:

// error handlers
// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
    message: err.message,
    error: err
// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
  message: err.message,
  error: {}

Is null check needed before calling instanceof?

Just as a tidbit:

Even (((A)null)instanceof A) will return false.

(If typecasting null seems surprising, sometimes you have to do it, for example in situations like this:

public class Test
  public static void test(A a)
    System.out.println("a instanceof A: " + (a instanceof A));

  public static void test(B b) {
    // Overloaded version. Would cause reference ambiguity (compile error)
    // if Test.test(null) was called without casting.
    // So you need to call Test.test((A)null) or Test.test((B)null).

So Test.test((A)null) will print a instanceof A: false.)

P.S.: If you are hiring, please don't use this as a job interview question. :D

How to close a JavaFX application on window close?

Did you try this..setOnCloseRequest

setOnCloseRequest(EventHandler<WindowEvent> value)   

There is one example

iOS - UIImageView - how to handle UIImage image orientation

Swift 3.1

func fixImageOrientation(_ image: UIImage)->UIImage {
    image.draw(at: .zero)
    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    return newImage ?? image

OCI runtime exec failed: exec failed: (...) executable file not found in $PATH": unknown

Get rid of your quotes around your command. When you quote it, docker tries to run the full string "lsb_release -a" as a command, which doesn't exist. Instead, you want to run the command lsb_release with an argument -a, and no quotes.

sudo docker exec -it c44f29d30753 lsb_release -a

Note, everything after the container name is the command and arguments to run inside the container, docker will not process any of that as options to the docker command.

How to convert int to float in python?

Other than John's answer, you could also make one of the variable float, and the result will yield float.

>>> 144 / 314.0

How to make scipy.interpolate give an extrapolated result beyond the input range?

Standard interpolate + linear extrapolate:

    def interpola(v, x, y):
        if v <= x[0]:
            return y[0]+(y[1]-y[0])/(x[1]-x[0])*(v-x[0])
        elif v >= x[-1]:
            return y[-2]+(y[-1]-y[-2])/(x[-1]-x[-2])*(v-x[-2])
            f = interp1d(x, y, kind='cubic') 
            return f(v)

How do I jump to a closing bracket in Visual Studio Code?

Details that can benefit everyone (Linux/Win/Mac)

The command in the keyboard shortcuts menu/editor is editor.action.jumpToBracket there you can set it to whatever you like. There is also one called editor.action.selectToBracket which has no shortcut by default (at least on Mac).


On the Mac editor.action.jumpToBracket starts out as Cmd+Shift+\ and I changed it to Ctrl+] because I didn't want a Shift in there and to be in line with what others here say works on Linux/Win. I did so in the hopes that I could use Ctrl+Shift+] to "Extend selection to matching bracket". That is what lead me to discover the details above. I set editor.action.selectToBracket to Ctrl+Shift+] and got exactly the behavior I wanted.

Compress images on client side before uploading

I'm late to the party, but this solution worked for me quite well. Based on this library, you can use a function lik this - setting the image, quality, max-width, and output format (jepg,png):

function compress(source_img_obj, quality, maxWidth, output_format){
    var mime_type = "image/jpeg";
    if(typeof output_format !== "undefined" && output_format=="png"){
        mime_type = "image/png";

    maxWidth = maxWidth || 1000;
    var natW = source_img_obj.naturalWidth;
    var natH = source_img_obj.naturalHeight;
    var ratio = natH / natW;
    if (natW > maxWidth) {
        natW = maxWidth;
        natH = ratio * maxWidth;

    var cvs = document.createElement('canvas');
    cvs.width = natW;
    cvs.height = natH;

    var ctx = cvs.getContext("2d").drawImage(source_img_obj, 0, 0, natW, natH);
    var newImageData = cvs.toDataURL(mime_type, quality/100);
    var result_image_obj = new Image();
    result_image_obj.src = newImageData;
    return result_image_obj;

Deck of cards JAVA

There is a lot of error in your program.

  1. Calculation of index. I think it should be Math.random()%deck.length

  2. In the display of card. According to me, you should make a class of card which has rank suit and make the array of that class type

If you want I can give you the Complete structure of that but it is better if u make it by yourself

Spring - No EntityManager with actual transaction available for current thread - cannot reliably process 'persist' call

For anyone with the same issue as I had, I was calling a public method method1 from within another class. method1 then called another public method method2 within the same class. method2 was annotated with @Transactional, but method1 was not. All that method1 did was transform some arguments and directly call method2, so no DB operations here.

The issue got solved for me once I moved the @Transactional annotation to method1.

Not sure the reason for this, but this did it for me.

isset() and empty() - what to use

$var = 'abcdef';
   if (strlen($var) > 0);
      //do something, string length greater than zero
     //do something else, string length 0 or less

This is a simple example. Hope it helps.

edit: added isset in the event a variable isn't defined like above, it would cause an error, checking to see if its first set at the least will help remove some headache down the road.

Saving binary data as file using JavaScript from a browser

Use FileSaver.js. It supports Chrome, Edge, Firefox, and IE 10+ (and probably IE < 10 with a few "polyfills" - see Note 4). FileSaver.js implements the saveAs() FileSaver interface in browsers that do not natively support it:

Minified version is really small at < 2.5KB, gzipped < 1.2KB.


/* TODO: replace the blob content with your byte[] */
var blob = new Blob([yourBinaryDataAsAnArrayOrAsAString], {type: "application/octet-stream"});
var fileName = "myFileName.myExtension";
saveAs(blob, fileName);

You might need Blob.js in some browsers (see Note 3). Blob.js implements the W3C Blob interface in browsers that do not natively support it. It is a cross-browser implementation:

Consider StreamSaver.js if you have files larger than blob's size limitations.

Complete example:

/* Two options_x000D_
 * 1. Get FileSaver.js from here_x000D_
 * -->_x000D_
 *     <script src="FileSaver.min.js" />_x000D_
 * Or_x000D_
 * 2. If you want to support only modern browsers like Chrome, Edge, Firefox, etc., _x000D_
 *    then a simple implementation of saveAs function can be:_x000D_
function saveAs(blob, fileName) {_x000D_
    var url = window.URL.createObjectURL(blob);_x000D_
    var anchorElem = document.createElement("a");_x000D_ = "display: none";_x000D_
    anchorElem.href = url;_x000D_ = fileName;_x000D_
    // On Edge, revokeObjectURL should be called only after_x000D_
    // has completed, atleast on EdgeHTML 15.15048_x000D_
    setTimeout(function() {_x000D_
    }, 1000);_x000D_
(function() {_x000D_
    // convert base64 string to byte array_x000D_
    var byteCharacters = atob("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");_x000D_
    var byteNumbers = new Array(byteCharacters.length);_x000D_
    for (var i = 0; i < byteCharacters.length; i++) {_x000D_
        byteNumbers[i] = byteCharacters.charCodeAt(i);_x000D_
    var byteArray = new Uint8Array(byteNumbers);_x000D_
    // now that we have the byte array, construct the blob from it_x000D_
    var blob1 = new Blob([byteArray], {type: "application/octet-stream"});_x000D_
    var fileName1 = "cool.gif";_x000D_
    saveAs(blob1, fileName1);_x000D_
    // saving text file_x000D_
    var blob2 = new Blob(["cool"], {type: "text/plain"});_x000D_
    var fileName2 = "cool.txt";_x000D_
    saveAs(blob2, fileName2);_x000D_

Tested on Chrome, Edge, Firefox, and IE 11 (use FileSaver.js for supporting IE 11).
You can also save from a canvas element. See


Blog post by author of FileSaver.js:

Note 1: Browser support:

Note 2: Failed to execute 'atob' on 'Window'

Note 3: Polyfill for browsers not supporting Blob:

Note 4: IE < 10 support (I've not tested this part):

Downloadify is a Flash-based polyfill for supporting IE6-9: (I don't recommend Flash-based solutions in general, though.)
Demo using Downloadify and FileSaver.js for supporting IE6-9 also:

Note 5: Creating a BLOB from a Base64 string in JavaScript

Note 6: FileSaver.js examples:

random.seed(): What does it do?

All the other answers don't seem to explain the use of random.seed(). Here is a simple example (source):

import random
random.seed( 3 )
print "Random number with seed 3 : ", random.random() #will generate a random number 
#if you want to use the same random number once again in your program
random.seed( 3 )
random.random()   # same random number as before

Extract substring using regexp in plain bash

    echo "US/Central - 10:26 PM (CST)" | sed -n "s/^.*-\s*\(\S*\).*$/\1/p"

-n      suppress printing
s       substitute
^.*     anything at the beginning
-       up until the dash
\s*     any space characters (any whitespace character)
\(      start capture group
\S*     any non-space characters
\)      end capture group
.*$     anything at the end
\1      substitute 1st capture group for everything on line
p       print it

How to activate "Share" button in android app?

Add a Button and on click of the Button add this code:

Intent sharingIntent = new Intent(android.content.Intent.ACTION_SEND); 
String shareBody = "Here is the share content body";
sharingIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, "Subject Here");
sharingIntent.putExtra(android.content.Intent.EXTRA_TEXT, shareBody);
startActivity(Intent.createChooser(sharingIntent, "Share via"));

Useful links:

For basic sharing

For customization

Rails 4 LIKE query - ActiveRecord adds quotes

While string interpolation will work, as your question specifies rails 4, you could be using Arel for this and keeping your app database agnostic.

def, page=1)
  query = "%#{query}%"
  name_match = arel_table[:name].matches(query)
  postal_match = arel_table[:postal_code].matches(query)

How to Generate Unique ID in Java (Integer)?

 import java.util.UUID;

 public class IdGenerator {
    public static int generateUniqueId() {      
        UUID idOne = UUID.randomUUID();
        String str=""+idOne;        
        int uid=str.hashCode();
        String filterStr=""+uid;
        str=filterStr.replaceAll("-", "");
        return Integer.parseInt(str);

    // XXX: replace with java.util.UUID

    public static void main(String[] args) {
        for (int i = 0; i < 5; i++) {


Hope this helps you.

Creating a URL in the controller .NET MVC

If you just want to get the path to a certain action, use UrlHelper:

UrlHelper u = new UrlHelper(this.ControllerContext.RequestContext);
string url = u.Action("About", "Home", null);

if you want to create a hyperlink:

string link = HtmlHelper.GenerateLink(this.ControllerContext.RequestContext, System.Web.Routing.RouteTable.Routes, "My link", "Root", "About", "Home", null, null);

Intellisense will give you the meaning of each of the parameters.

Update from comments: controller already has a UrlHelper:

string url = this.Url.Action("About", "Home", null); 

Fastest way to download a GitHub project

Another faster way of downloading a GitHub project would be to use the clone functionality with the --depth argument as:

git clone --depth=1 [email protected]:organization/your-repo.git

to perform a shallow clone.

No suitable records were found verify your bundle identifier is correct

iTunes Connect || App Store Connect (website):

In your browser, go to iTunes connect/ App Store Connect.

  1. Add your New App / edit your existing app.
  2. Go to App information.
  3. Check the Bundle ID name.
  4. If there is no bundle ID, make sure you create one.
  5. I used the WildCard bundle ID. That means, your complete bundle ID is likely to be com.organizationName.* and the suffix (exampleApp). Xcode:
  6. Go to your Workspace / Project.
  7. Go to your project.
  8. Select the General Tab.

Ensure the Bundle Identifier is the name you set in iTunes Connect.

For example: com.orgnanizationName.appName

It seems you have to start the App Store submission process in iTunesConnect.

App Store Connect Icon Add App

Running JAR file on Windows 10

How do I run an executable JAR file? If you have a jar file called Example.jar, follow these rules:

Open a notepad.exe.
Write : java -jar Example.jar.
Save it with the extension .bat.
Copy it to the directory which has the .jar file.
Double click it to run your .jar file.

Are lists thread-safe?

Lists themselves are thread-safe. In CPython the GIL protects against concurrent accesses to them, and other implementations take care to use a fine-grained lock or a synchronized datatype for their list implementations. However, while lists themselves can't go corrupt by attempts to concurrently access, the lists's data is not protected. For example:

L[0] += 1

is not guaranteed to actually increase L[0] by one if another thread does the same thing, because += is not an atomic operation. (Very, very few operations in Python are actually atomic, because most of them can cause arbitrary Python code to be called.) You should use Queues because if you just use an unprotected list, you may get or delete the wrong item because of race conditions.

What is ".NET Core"?

I was trying to create a new project in Visual Studio 2017 today (recently upgraded from Visual Studio 2015) and noticed new set of choices for the type of project. Either they're new or it's been a while since I started a new project!! :)

Visual Studio Screenshot

I came across this documentation link and found it very useful, so I am sharing. The details of the bullets are also provided in the article. I am just posting bullets here:

You should use .NET Core for your server application when:

You have cross-platform needs.
You are targeting microservices.
You are using Docker containers.
You need high performance and scalable systems.
You need side by side of .NET versions by application.

You should use .NET Framework for your server application when:

Your application currently uses .NET Framework (recommendation is to extend instead of migrating)
You need to use third-party .NET libraries or NuGet packages not available for .NET Core.
You need to use .NET technologies that are not available for .NET Core.
You need to use a platform that doesn’t support .NET Core.

This link provides a glossary of .NET terms.

EDIT 10/7/2020 Check out .NET 5.0 - "... just one .NET going forward, and you will be able to use it to target Windows, Linux, macOS, iOS, Android, tvOS, watchOS and WebAssembly and more" It's supposed to be released November 2020.

How to query between two dates using Laravel and Eloquent?

I know this might be an old question but I just found myself in a situation where I had to implement this feature in a Laravel 5.7 app. Below is what worked from me.

 $articles = Articles::where("created_at",">", Carbon::now()->subMonths(3))->get();

You will also need to use Carbon

use Carbon\Carbon;

How to speed up insertion performance in PostgreSQL

I encountered this insertion performance problem as well. My solution is spawn some go routines to finish the insertion work. In the meantime, SetMaxOpenConns should be given a proper number otherwise too many open connection error would be alerted.

db, _ := 
var wg sync.WaitGroup
for _, query := range queries {
    go func(msg string) {
        defer wg.Done()
        _, err := db.Exec(msg)
        if err != nil {

The loading speed is much faster for my project. This code snippet just gave an idea how it works. Readers should be able to modify it easily.

Algorithm to generate all possible permutations of a list?

In Scala

    def permutazione(n: List[Int]): List[List[Int]] = permutationeAcc(n, Nil)

def permutationeAcc(n: List[Int], acc: List[Int]): List[List[Int]] = {

    var result: List[List[Int]] = Nil
    for (i ? n if (!(acc contains (i))))
        if (acc.size == n.size-1)
            result = (i :: acc) :: result
            result = result ::: permutationeAcc(n, i :: acc)

Python 3 - Encode/Decode vs Bytes/Str

To add to Lennart Regebro's answer There is even the third way that can be used:

encoded3 = str.encode(original, 'utf-8')

Anyway, it is actually exactly the same as the first approach. It may also look that the second way is a syntactic sugar for the third approach.

A programming language is a means to express abstract ideas formally, to be executed by the machine. A programming language is considered good if it contains constructs that one needs. Python is a hybrid language -- i.e. more natural and more versatile than pure OO or pure procedural languages. Sometimes functions are more appropriate than the object methods, sometimes the reverse is true. It depends on mental picture of the solved problem.

Anyway, the feature mentioned in the question is probably a by-product of the language implementation/design. In my opinion, this is a nice example that show the alternative thinking about technically the same thing.

In other words, calling an object method means thinking in terms "let the object gives me the wanted result". Calling a function as the alternative means "let the outer code processes the passed argument and extracts the wanted value".

The first approach emphasizes the ability of the object to do the task on its own, the second approach emphasizes the ability of an separate algoritm to extract the data. Sometimes, the separate code may be that much special that it is not wise to add it as a general method to the class of the object.

How to return a value from try, catch, and finally?

To return a value when using try/catch you can use a temporary variable, e.g.

public static double add(String[] values) {
    double sum = 0.0;
    try {
        int length = values.length;
        double arrayValues[] = new double[length];
        for(int i = 0; i < length; i++) {
            arrayValues[i] = Double.parseDouble(values[i]);
            sum += arrayValues[i];
    } catch(NumberFormatException e) {
    } catch(RangeException e) {
        throw e;
    } finally {
        System.out.println("Thank you for using the program!");
    return sum;

Else you need to have a return in every execution path (try block or catch block) that has no throw.

Dynamically select data frame columns using $ and a character value

You can't do that kind of subsetting with $. In the source code (R/src/main/subset.c) it states:

/*The $ subset operator.
We need to be sure to only evaluate the first argument.
The second will be a symbol that needs to be matched, not evaluated.

Second argument? What?! You have to realise that $, like everything else in R, (including for instance ( , + , ^ etc) is a function, that takes arguments and is evaluated. df$V1 could be rewritten as

`$`(df , V1)

or indeed

`$`(df , "V1")


`$`(df , paste0("V1") )

...for instance will never work, nor will anything else that must first be evaluated in the second argument. You may only pass a string which is never evaluated.

Instead use [ (or [[ if you want to extract only a single column as a vector).

For example,

var <- "mpg"
#Doesn't work
#These both work, but note that what they return is different
# the first is a vector, the second is a data.frame

You can perform the ordering without loops, using to construct the call to order. Here is a reproducible example below:

#  set seed for reproducibility
df <- data.frame( col1 = sample(5,10,repl=T) , col2 = sample(5,10,repl=T) , col3 = sample(5,10,repl=T) )

#  We want to sort by 'col3' then by 'col1'
sort_list <- c("col3","col1")

#  Use '' to call order. Seccond argument in is a list of arguments
#  to pass to the first argument, in this case 'order'.
#  Since  a data.frame is really a list, we just subset the data.frame
#  according to the columns we want to sort in, in that order
df[ order , df[ , match( sort_list , names(df) ) ]  ) , ]

   col1 col2 col3
10    3    5    1
9     3    2    2
7     3    2    3
8     5    1    3
6     1    5    4
3     3    4    4
2     4    3    4
5     5    1    4
1     2    5    5
4     5    3    5

nvarchar(max) vs NText

Wanted to add my experience with converting. I had many text fields in ancient Linq2SQL code. This was to allow text columns present in indexes to be rebuilt ONLINE.

First I've known about the benefits for years, but always assumed that converting would mean some scary long queries where SQL Server would have to rebuild the table and copy everything over, bringing down my websites and raising my heartrate.

I was also concerned that the Linq2SQL could cause errors if it was doing some kind of verification of the column type.

Happy to report though, that the ALTER commands returned INSTANTLY - so they are definitely only changing table metadata. There may be some offline work happening to bring <8000 character data back to be in-table, but the ALTER command was instant.

I ran the following to find all columns needing conversion:

SELECT concat('ALTER TABLE dbo.[', table_name, '] ALTER COLUMN [', column_name, '] VARCHAR(MAX)'), table_name, column_name
FROM information_schema.columns where data_type = 'TEXT' order by table_name, column_name

SELECT concat('ALTER TABLE dbo.[', table_name, '] ALTER COLUMN [', column_name, '] NVARCHAR(MAX)'), table_name, column_name
FROM information_schema.columns where data_type = 'NTEXT' order by table_name, column_name

This gave me a nice list of queries, which I just selected and copied to a new window. Like I said - running this was instant.

enter image description here

Linq2SQL is pretty ancient - it uses a designer that you drag tables onto. The situation may be more complex for EF Code first but I haven't tackled that yet.

Export to xls using angularjs

$scope.ExportExcel= function () { //function define in html tag                          

                        //export to excel file
                        var tab_text = '<table border="1px" style="font-size:20px" ">';
                        var textRange;
                        var j = 0;
                        var tab = document.getElementById('TableExcel'); // id of table
                        var lines = tab.rows.length;

                        // the first headline of the table
                        if (lines > 0) {
                            tab_text = tab_text + '<tr bgcolor="#DFDFDF">' + tab.rows[0].innerHTML + '</tr>';

                        // table data lines, loop starting from 1
                        for (j = 1 ; j < lines; j++) {
                            tab_text = tab_text + "<tr>" + tab.rows[j].innerHTML + "</tr>";                                

                        tab_text = tab_text + "</table>";
                        tab_text = tab_text.replace(/<A[^>]*>|<\/A>/g, "");          //remove if u want links in your table
                        tab_text = tab_text.replace(/<img[^>]*>/gi, "");             // remove if u want images in your table
                        tab_text = tab_text.replace(/<input[^>]*>|<\/input>/gi, ""); // reomves input params

                        // console.log(tab_text); // aktivate so see the result (press F12 in browser)               
                        var fileName = 'report.xls'                            
                        var exceldata = new Blob([tab_text], { type: "application/;charset=utf-8" }) 

                        if (window.navigator.msSaveBlob) { // IE 10+
                            window.navigator.msSaveOrOpenBlob(exceldata, fileName);
                            //$scope.DataNullEventDetails = true;
                        } else {
                            var link = document.createElement('a'); //create link download file
                            link.href = window.URL.createObjectURL(exceldata); // set url for link download
                            link.setAttribute('download', fileName); //set attribute for link created


        //html of button 

Cannot use a CONTAINS or FREETEXT predicate on table or indexed view because it is not full-text indexed

Select * from table
where CONTAINS([Column], '"A00*"')  

will act as % same as

where [Column] Like 'A00%'

Latest jQuery version on Google's CDN

I don't know if/where it's published, but you can get the latest release by omitting the minor and build numbers.

Latest 1.8.x:

<script src="//"></script>

Latest 1.x:

<script src="//"></script>

However, do keep in mind that these links have a much shorter cache timeout than with the full version number, so your users may be downloading them more than you'd like. See The crucial .0 in Google CDN references to jQuery 1.x.0 for more information.

In Java, what does NaN mean?

NaN means “Not a Number” and is basically a representation of a special floating point value in the IEE 754 floating point standard. NaN generally means that the value is something that cannot be expressed with a valid floating point number.

A conversion will result in this value, when the value being converted is something else, for example when converting a string that does not represent a number.

Read file from aws s3 bucket using node fs

Since you seem to want to process an S3 text file line-by-line. Here is a Node version that uses the standard readline module and AWS' createReadStream()

const readline = require('readline');

const rl = readline.createInterface({
    input: s3.getObject(params).createReadStream()

rl.on('line', function(line) {
.on('close', function() {

Bootstrap 3 only for mobile

If you're looking to make the elements be 33.3% only on small devices and lower:

This is backwards from what Bootstrap is designed for, but you can do this:

<div class="row">
    <div class="col-xs-4 col-md-12">.col-xs-4 .col-md-12</div>
    <div class="col-xs-4 col-md-12">.col-xs-4 .col-md-12</div>
    <div class="col-xs-4 col-md-12">.col-xs-4 .col-md-12</div>

This will make each element 33.3% wide on small and extra small devices but 100% wide on medium and larger devices.


If you're only looking to hide elements for smaller devices:

I think you're looking for the visible-xs and/or visible-sm classes. These will let you make certain elements only visible to small screen devices.

For example, if you want a element to only be visible to small and extra-small devices, do this:

<div class="visible-xs visible-sm">You're using a fairly small device.</div>

To show it only for larger screens, use this:

<div class="hidden-xs hidden-sm">You're probably not using a phone.</div>

See for more information.

Spring .properties file: get element as an Array

With a Spring Boot one can do the following:


Configuration class

import org.springframework.stereotype.Component;

import java.util.ArrayList;
import java.util.List;

public class Configuration {

    List<String> values = new ArrayList<>();

    public List<String> getValues() {
        return values;


This is needed, without this class or without the values in class it is not working.

Spring Boot Application class

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import java.util.List;

public class SpringBootConsoleApplication implements CommandLineRunner {

    private static Logger LOG = LoggerFactory.getLogger(SpringBootConsoleApplication.class);

    // notice #{} is used instead of ${}
    List<String> values;

    public static void main(String[] args) {, args);

    public void run(String... args) {"values: {}", values);


Convert text to columns in Excel using VBA

If someone is facing issue using texttocolumns function in UFT. Please try using below function.

myxl.Workbooks.Open myexcel.xls
myxl.Application.Visible = false `enter code here`
set mysheet = myxl.ActiveWorkbook.Worksheets(1)
Set objRange = myxl.Range("A1").EntireColumn
Set objRange2 = mysheet.Range("A1")
objRange.TextToColumns objRange2,1,1, , , , true

Here we are using coma(,) as delimiter.

Visual Studio Code Search and Replace with Regular Expressions

So, your goal is to search and replace?
According to the Official Visual Studio's keyboard shotcuts pdf, you can press Ctrl + H on Windows and Linux, or ??F on Mac to enable search and replace tool:

Visual studio code's search & replace tab If you mean to disable the code, you just have to put <h1> in search, and replace to ####.

But if you want to use this regex instead, you may enable it in the icon: .* and use the regex: <h1>(.+?)<\/h1> and replace to: #### $1.

And as @tpartee suggested, here is some more information about Visual Studio's engine if you would like to learn more:

How to change default language for SQL Server?

If you want to change MSSQL server language, you can use the following QUERY:

EXEC sp_configure 'default language', 'British English';

How can I center text (horizontally and vertically) inside a div block?

Really simple code that works for me! Just one line and your text will be centered horizontally.

  justify-content: center;

<Card.Footer className="card-body-padding center-horizontally">
  <label className="support-expand-text-light">Call or email Customer Support to change</label>

The output looks like this:

Please vote this answer if it works for just to spare some time of devs looking for easy solutions. Thanks! :)

Joining pandas dataframes by column names

you can use the left_on and right_on options as follows:

pd.merge(frame_1, frame_2, left_on='county_ID', right_on='countyid')

I was not sure from the question if you only wanted to merge if the key was in the left hand dataframe. If that is the case then the following will do that (the above will in effect do a many to many merge)

pd.merge(frame_1, frame_2, how='left', left_on='county_ID', right_on='countyid')

How to get year, month, day, hours, minutes, seconds and milliseconds of the current moment in Java?

    // Java 8
    System.out.println(;       // 2015
    System.out.println(;      // SEPTEMBER
    System.out.println(; // 29
    System.out.println(;       // 7
    System.out.println(;     // 36
    System.out.println(;     // 51
    System.out.println(; // 100

    // Calendar
    System.out.println(Calendar.getInstance().get(Calendar.YEAR));         // 2015
    System.out.println(Calendar.getInstance().get(Calendar.MONTH ) + 1);   // 9
    System.out.println(Calendar.getInstance().get(Calendar.DAY_OF_MONTH)); // 29
    System.out.println(Calendar.getInstance().get(Calendar.HOUR_OF_DAY));  // 7
    System.out.println(Calendar.getInstance().get(Calendar.MINUTE));       // 35
    System.out.println(Calendar.getInstance().get(Calendar.SECOND));       // 32
    System.out.println(Calendar.getInstance().get(Calendar.MILLISECOND));  // 481

    // Joda Time
    System.out.println(new DateTime().getYear());           // 2015
    System.out.println(new DateTime().getMonthOfYear());    // 9
    System.out.println(new DateTime().getDayOfMonth());     // 29
    System.out.println(new DateTime().getHourOfDay());      // 7
    System.out.println(new DateTime().getMinuteOfHour());   // 19
    System.out.println(new DateTime().getSecondOfMinute()); // 16
    System.out.println(new DateTime().getMillisOfSecond()); // 174

    // Formatted
    // 2015-09-28 17:50:25.756
    System.out.println(new Timestamp(System.currentTimeMillis()));

    // 2015-09-28T17:50:25.772
    System.out.println(new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS", Locale.ENGLISH).format(new Date()));

    // Java 8
    // 2015-09-28T17:50:25.810

    // joda time
    // 2015-09-28 17:50:25.839
    System.out.println(DateTimeFormat.forPattern("YYYY-MM-dd HH:mm:ss.SSS").print(new org.joda.time.DateTime()));

Call of overloaded function is ambiguous

The literal 0 has two meanings in C++.
On the one hand, it is an integer with the value 0.
On the other hand, it is a null-pointer constant.

As your setval function can accept either an int or a char*, the compiler can not decide which overload you meant.

The easiest solution is to just cast the 0 to the right type.
Another option is to ensure the int overload is preferred, for example by making the other one a template:

class huge
  unsigned char data[BYTES];
  void setval(unsigned int);
  template <class T> void setval(const T *); // not implemented
  template <> void setval(const char*);

iPhone keyboard, Done button and resignFirstResponder

I used this method to change choosing Text Field

- (BOOL)textFieldShouldReturn:(UITextField *)textField {

if ([textField isEqual:self.emailRegisterTextField]) {

    [self.usernameRegisterTextField becomeFirstResponder];

} else if ([textField isEqual:self.usernameRegisterTextField]) {

    [self.passwordRegisterTextField becomeFirstResponder];

} else {

    [textField resignFirstResponder];

    // To click button for registration when you clicking button "Done" on the keyboard
    [self createMyAccount:self.registrationButton];

return YES;


How do I create an Android Spinner as a popup?

You can use an alert dialog

    AlertDialog.Builder b = new Builder(this);
    String[] types = {"By Zip", "By Category"};
    b.setItems(types, new OnClickListener() {

        public void onClick(DialogInterface dialog, int which) {

            case 0:
            case 1:


This will close the dialog when one of them is pressed like you are wanting. Hope this helps!

How to reset sequence in postgres and fill id column with new data?

To retain order of the rows:

UPDATE thetable SET rowid=col_serial FROM 
(SELECT rowid, row_number() OVER ( ORDER BY lngid) AS col_serial FROM thetable ORDER BY lngid) AS t1 
WHERE thetable.rowid=t1.rowid;

Use css gradient over background image

 box-sizing: border-box;_x000D_
 width: 123px;_x000D_
 height: 30px;_x000D_
 font-size: 12pt;_x000D_
 border-radius: 7px;  _x000D_
 background: url(""), linear-gradient(to bottom, #4ac425, #4ac425);_x000D_
 background-repeat: no-repeat, repeat;_x000D_
 background-position: 5px center, 0px 0px;_x000D_
    background-size: 18px 18px, 100% 100%;_x000D_
 color: white; _x000D_
 border: 1px solid #e4f6df;_x000D_
 box-shadow: .25px .25px .5px .5px black;_x000D_
 padding: 3px 10px 0px 5px;_x000D_
 text-align: right;_x000D_
<div id="multiple-background"> Completed </div>

How to add Tomcat Server in eclipse

Most of the time when we download tomcat and extract the file a folder will be created:

C:\Program Files\apache-tomcat-9.0.1-windows-x64

Inside that actual tomcat folder will be there:

C:\Program Files\apache-tomcat-9.0.1-windows-x64\apache-tomcat-9.0.1

so while selecting you need to select inner folder:

C:\Program Files\apache-tomcat-9.0.1-windows-x64\apache-tomcat-9.0.1

instead of the outer.

How do you connect to multiple MySQL databases on a single webpage?

Instead of mysql_connect use mysqli_connect.

mysqli is provide a functionality for connect multiple database at a time.

$Db1 = new mysqli($hostname,$username,$password,$db_name1); 
// this is connection 1 for DB 1

$Db2 = new mysqli($hostname,$username,$password,$db_name2); 
// this is connection 2 for DB 2

Assign output of os.system to a variable and prevent it from being displayed on the screen

from os import system, remove
from uuid import uuid4

def bash_(shell_command: str) -> tuple:

    :param shell_command: your shell command
    :return: ( 1 | 0, stdout)

    logfile: str = '/tmp/%s' % uuid4().hex
    err: int = system('%s &> %s' % (shell_command, logfile))
    out: str = open(logfile, 'r').read()
    return err, out

# Example: 
print(bash_('cat /usr/bin/vi | wc -l'))
>>> (0, '3296\n')```

#ifdef in C#

I would recommend you using the Conditional Attribute!

Update: 3.5 years later

You can use #if like this (example copied from MSDN):

// preprocessor_if.cs
#define DEBUG
#define VC_V7
using System;
public class MyClass 
    static void Main() 
#if (DEBUG && !VC_V7)
        Console.WriteLine("DEBUG is defined");
#elif (!DEBUG && VC_V7)
        Console.WriteLine("VC_V7 is defined");
#elif (DEBUG && VC_V7)
        Console.WriteLine("DEBUG and VC_V7 are defined");
        Console.WriteLine("DEBUG and VC_V7 are not defined");

Only useful for excluding parts of methods.

If you use #if to exclude some method from compilation then you will have to exclude from compilation all pieces of code which call that method as well (sometimes you may load some classes at runtime and you cannot find the caller with "Find all references"). Otherwise there will be errors.

If you use conditional compilation on the other hand you can still leave all pieces of code that call the method. All parameters will still be validated by the compiler. The method just won't be called at runtime. I think that it is way better to hide the method just once and not have to remove all the code that calls it as well. You are not allowed to use the conditional attribute on methods which return value - only on void methods. But I don't think this is a big limitation because if you use #if with a method that returns a value you have to hide all pieces of code that call it too.

Here is an example:

    // calling Class1.ConditionalMethod() will be ignored at runtime 
    // unless the DEBUG constant is defined

    using System.Diagnostics;
    class Class1 
       public static void ConditionalMethod() {
          Console.WriteLine("Executed Class1.ConditionalMethod");


I would use #ifdef in C++ but with C#/VB I would use Conditional attribute. This way you hide the method definition without having to hide the pieces of code that call it. The calling code is still compiled and validated by the compiler, the method is not called at runtime though. You may want to use #if to avoid dependencies because with Conditional attribute your code is still compiled.

What is makeinfo, and how do I get it?

A few words on "what is makeinfo" -- other answers cover "how do I get it" well.

The section "Creating an Info File" of the Texinfo manual states that

makeinfo is a program that converts a Texinfo file into an Info file, HTML file, or plain text.

The Texinfo home page explains that Texinfo itself "is the official documentation format of the GNU project" and that it "uses a single source file to produce output in a number of formats, both online and printed (dvi, html, info, pdf, xml, etc.)".

To sum up: Texinfo is a documentation source file format and makeinfo is the program that turns source files in Texinfo format into the desired output.

What's the difference between using "let" and "var"?

Before 2015, using the var keyword was the only way to declare a JavaScript variable.

After ES6 (a JavaScript version), it allows 2 new keywords let & const.

let = can be re-assigned
const = cannot be re-assigned ( const which comes from constant, short-form 'const' )


  • Suppose, declaring a Country Name / Your mother name, const is most suitable here. because there is less chance to change a country name or your mother name soon or later.

  • Your age, weight, salary, speed of a bike and more like these types of data that change often or need to reassign. those situations, let is used.

What are sessions? How do they work?

Simple Explanation by analogy

Imagine you are in a bank, trying to get some money out of your account. But it's dark; the bank is pitch black: there's no light and you can't see your hand in front of your face. You are surrounded by another 20 people. They all look the same. And everybody has the same voice. And everyone is a potential bad guy. In other words, HTTP is stateless.

This bank is a funny type of bank - for the sake of argument here's how things work:

  1. you wait in line (or on-line) and you talk to the teller: you make a request to withdraw money, and then
  2. you have to wait briefly on the sofa, and 20 minutes later
  3. you have to go and actually collect your money from the teller.

But how will the teller tell you apart from everyone else?

The teller can't see or readily recognise you, remember, because the lights are all out. What if your teller gives your $10,000 withdrawal to someone else - the wrong person?! It's absolutely vital that the teller can recognise you as the one who made the withdrawal, so that you can get the money (or resource) that you asked for.


When you first appear to the teller, he or she tells you something in secret:

"When ever you are talking to me," says the teller, "you should first identify yourlself as GNASHEU329 - that way I know it's you".

Nobody else knows the secret passcode.

Example of How I Withdrew Cash:

So I decide to go to and chill out for 20 minutes and then later i go to the teller and say "I'd like to collect my withdrawal"

The teller asks me: "who are you??!"

"It's me, Mr George Banks!"

"Prove it!"

And then I tell them my passcode: GNASHEU329

"Certainly Mr Banks!"

That basically is how a session works. It allows one to be uniquely identified in a sea of millions of people. You need to identify yourself every time you deal with the teller.

If you got any questions or are unclear - please post comment and i will try to clear it up for you. The following is not strictly speaking, completely accurate in its terminology, but I hope it's helpful to you in understanding concepts.

Explanation via Pictures:

Sessions explained via Picture

What is the simplest C# function to parse a JSON string into an object?

You should create a structure that represents JSON keys (in case if you exactly know it) and then you can easily deserialize JSON string into your structure. In my examle I've deserialized a response from Google Cloud Message server:

class templateResponse
    public String multicast_id;
    public String success;
    public String failure;
    public String canonical_ids;
    public Result[] results;

    public class Result
        public String message_id;
        public String registration_id;
        public String error;

incoming JSON was:


So, use

templateResponse result = new JavaScriptSerializer().Deserialize<templateResponse>(json);

and you will get deserialized result object

Facebook Javascript SDK Problem: "FB is not defined"

I had the same problem and I've found the cause.

I have avast! antivirus installed in my computer, and it asked me to install the update for chrome plugin. The new avast! plugin for chrome has the functionality to block ads and tracking, and, by default, it blocks the facebook access. I have solved my problem simply allowing facebook in the avast! chrome plugin for the website I needed.

Since this question is very old, I think that some people might have the same cause as me, the new avast! chrome plugin.

How to test valid UUID/GUID?

thanks to @usertatha with some modification

function isUUID ( uuid ) {
    let s = "" + uuid;

    s = s.match('^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$');
    if (s === null) {
      return false;
    return true;

Git Pull While Ignoring Local Changes?

I usually do:

git checkout .
git pull

In the project's root folder.

Update Rows in SSIS OLEDB Destination

You can't do a bulk-update in SSIS within a dataflow task with the OOB components.

The general pattern is to identify your inserts, updates and deletes and push the updates and deletes to a staging table(s) and after the Dataflow Task, use a set-based update or delete in an Execute SQL Task. Look at Andy Leonard's Stairway to Integration Services series. Scroll about 3/4 the way down the article to "Set-Based Updates" to see the pattern.

Stage data

Set based updates

enter image description here

You'll get much better performance with a pattern like this versus using the OLE DB Command transformation for anything but trivial amounts of data.

If you are into third party tools, I believe CozyRoc and I know PragmaticWorks have a merge destination component.

Select current element in jQuery

Fortunately, jQuery selectors allow you much more freedom:

$("div a").click( function(event)
   var clicked = $(this); // jQuery wrapper for clicked element
   // ... click-specific code goes here ...

...will attach the specified callback to each <a> contained in a <div>.

How to print a dictionary line by line in Python?

You have a nested structure, so you need to format the nested dictionary too:

for key, car in cars.items():
    for attribute, value in car.items():
        print('{} : {}'.format(attribute, value))

This prints:

color : 2
speed : 70
color : 3
speed : 60

What are the differences between Deferred, Promise and Future in JavaScript?

  • A promise represents a value that is not yet known
  • A deferred represents work that is not yet finished

A promise is a placeholder for a result which is initially unknown while a deferred represents the computation that results in the value.


How to create a Custom Dialog box in android?

It's a class for Alert Dialog so that u can call the class from any activity to reuse the code.

public class MessageOkFragmentDialog extends DialogFragment {
Typeface Lato;
String message = " ";
String title = " ";
int messageID = 0;

public MessageOkFragmentDialog(String message, String title) {
    this.message = message;
    this.title = title;

public Dialog onCreateDialog(Bundle savedInstanceState) {

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

    LayoutInflater inflater = getActivity().getLayoutInflater();

    View convertview = inflater.inflate(R.layout.dialog_message_ok_box, null);

    Constants.overrideFonts(getActivity(), convertview);
    Lato = Typeface
            .createFromAsset(getActivity().getAssets(), "font/Lato-Regular.ttf");

    TextView textmessage = (TextView) convertview

    TextView textview_dialog_title = (TextView) convertview.findViewById(;



    Button button_ok = (Button) convertview

    button_ok.setOnClickListener(new OnClickListener() {
        public void onClick(View arg0) {


    return builder.create();


Xml file for the same is:

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=""



                android:textSize="@dimen/txtSize_Medium" />


            android:background="@color/txt_white_color" />

            android:textSize="@dimen/txtSize_small" />



            android:textSize="@dimen/txtSize_small" />


Check if a class is derived from a generic class

(Reposted due to a massive rewrite)

JaredPar's code answer is fantastic, but I have a tip that would make it unnecessary if your generic types are not based on value type parameters. I was hung up on why the "is" operator would not work, so I have also documented the results of my experimentation for future reference. Please enhance this answer to further enhance its clarity.


If you make certain that your GenericClass implementation inherits from an abstract non-generic base class such as GenericClassBase, you could ask the same question without any trouble at all like this:



My testing indicates that IsSubclassOf() does not work on parameterless generic types such as


whereas it will work with


Therefore the following code will work for any derivation of GenericClass<>, assuming you are willing to test based on SomeType:


The only time I can imagine that you would want to test by GenericClass<> is in a plug-in framework scenario.

Thoughts on the "is" operator

At design-time C# does not allow the use of parameterless generics because they are essentially not a complete CLR type at that point. Therefore, you must declare generic variables with parameters, and that is why the "is" operator is so powerful for working with objects. Incidentally, the "is" operator also can not evaluate parameterless generic types.

The "is" operator will test the entire inheritance chain, including interfaces.

So, given an instance of any object, the following method will do the trick:

bool IsTypeof<T>(object t)
    return (t is T);

This is sort of redundant, but I figured I would go ahead and visualize it for everybody.


var t = new Test();

The following lines of code would return true:

bool test1 = IsTypeof<GenericInterface<SomeType>>(t);

bool test2 = IsTypeof<GenericClass<SomeType>>(t);

bool test3 = IsTypeof<Test>(t);

On the other hand, if you want something specific to GenericClass, you could make it more specific, I suppose, like this:

bool IsTypeofGenericClass<SomeType>(object t)
    return (t is GenericClass<SomeType>);

Then you would test like this:

bool test1 = IsTypeofGenericClass<SomeType>(t);

How to Add a Dotted Underline Beneath HTML Text

If the content has more than 1 line, adding a bottom border won't help. In that case you'll have to use,

text-decoration: underline;
text-decoration-style: dotted;

If you want more breathing space in between the text and the line, simply use,

text-underline-position: under;

data.frame rows to a list

An alternative way is to convert the df to a matrix then applying the list apply lappy function over it: ldf <- lapply(as.matrix(myDF), function(x)x)

Excel CSV - Number cell format

The Text Import Wizard method does NOT work when the CSV file being imported has line breaks within a cell. This method handles this scenario(at least with tab delimited data):

  1. Create new Excel file
  2. Ctrl+A to select all cells
  3. In Number Format combobox, select Text
  4. Open tab delimited file in text editor
  5. Select all, copy and paste into Excel

iPad Multitasking support requires these orientations

I am using Xamarin and there is no available option in the UI to specify "Requires full screen". I, therefore, had to follow @Michael Wang's answer with a slight modification. Here goes:

Open the info.plist file in a text editor and add the lines:


I tried setting the value to "YES" but it didn't work, which was kind of expected.

In case you are wondering, I placed the above lines below the UISupportedInterfaceOrientations section


Hope this helps someone. Credit to Michael.

ORDER BY the IN value list

create sequence serial start 1;

select * from comments c
join (select unnest(ARRAY[1,3,2,4]) as id, nextval('serial') as id_sorter) x
on =
order by x.id_sorter;

drop sequence serial;


unnest is not yet built-in in 8.3, but you can create one yourself(the beauty of any*):

create function unnest(anyarray) returns setof anyelement
language sql as
    select $1[i] from generate_series(array_lower($1,1),array_upper($1,1)) i;

that function can work in any type:

select unnest(array['John','Paul','George','Ringo']) as beatle
select unnest(array[1,3,2,4]) as id

Printing everything except the first field with awk

Maybe the most concise way:

$ awk '{$(NF+1)=$1;$1=""}sub(FS,"")' infile
United Arab Emirates AE
Antigua & Barbuda AG
Netherlands Antilles AN
American Samoa AS
Bosnia and Herzegovina BA
Burkina Faso BF
Brunei Darussalam BN


$(NF+1)=$1: Generator of a "new" last field.

$1="": Set the original first field to null

sub(FS,""): After the first two actions {$(NF+1)=$1;$1=""} get rid of the first field separator by using sub. The final print is implicit.

Getting Serial Port Information

There is a post about this same issue on MSDN:

Getting more information about a serial port in C#

Hi Ravenb,

We can't get the information through the SerialPort type. I don't know why you need this info in your application. However, there's a solved thread with the same question as you. You can check out the code there, and see if it can help you.

If you have any further problem, please feel free to let me know.

Best regards, Bruce Zhou

The link in that post goes to this one:

How to get more info about port using System.IO.Ports.SerialPort

You can probably get this info from a WMI query. Check out this tool to help you find the right code. Why would you care though? This is just a detail for a USB emulator, normal serial ports won't have this. A serial port is simply know by "COMx", nothing more.

How do I disable directory browsing?

Create an .htaccess file containing the following line:

Options -Indexes

That is one option. Another option is editing your apache configuration file.

In order to do so, you first need to open it with the command:

vim /etc/httpd/conf/httpd.conf

Then find the line: Options Indexes FollowSymLinks

Change that line to: Options FollowSymLinks

Lastly save and exit the file, and restart apache server with this command:

sudo service httpd restart

(You have a guide with screenshots here.)

Collision Detection between two images in Java

I think your problem is that you are not using good OO design for your player and enemies. Create two classes:

public class Player
    int X;
    int Y;
    int Width;
    int Height;

    // Getters and Setters

public class Enemy
    int X;
    int Y;
    int Width;
    int Height;

    // Getters and Setters

Your Player should have X,Y,Width,and Height variables.

Your enemies should as well.

In your game loop, do something like this (C#):

foreach (Enemy e in EnemyCollection)
    Rectangle r = new Rectangle(e.X,e.Y,e.Width,e.Height);
    Rectangle p = new Rectangle(player.X,player.Y,player.Width,player.Height);

    // Assuming there is an intersect method, otherwise just handcompare the values
    if (r.Intersects(p))
       // A Collision!
       // we know which enemy (e), so we can call e.DoCollision();

To speed things up, don't bother checking if the enemies coords are offscreen.

What does $1 mean in Perl?

As others have pointed out, the $x are capture variables for regular expressions, allowing you to reference sections of a matched pattern.

Perl also supports named captures which might be easier for humans to remember in some cases.

Given input: 111 222


$1 is 111

$2 is 222

One could also say:


$+{myvara} is 111

$+{myvarb} is 222